Calculators

The Amortization Calculator helps you estimate monthly payments and generate customized amortization schedules based on your loan amount, term, and interest rate.

Estimate your monthly auto lease payments, total depreciation, and rent charges with our modern auto lease calculator.

Estimate your monthly car payments, total interest, and the true cost of your next vehicle purchase with our comprehensive auto loan calculator.

Calculate your monthly boat payment, total interest, and full amortization schedule — including down payment and trade-in value.

Estimate your business loan monthly payment, net proceeds after origination fees, and total cost over the life of the loan.

Calculate your Canadian mortgage payment using legally-mandated semi-annual compounding, plus the remaining balance you'll actually owe at renewal time.

Compare auto manufacturer incentives to determine if a cash back rebate or a low promotional interest rate offers better long-term savings on your car purchase.

Find out how long it will take to pay off your credit card balance, how much interest you'll pay, and how much the minimum-payment trap really costs.

Compare paying off several existing debts separately against rolling them into a single consolidation loan, and see the real savings (or cost) in interest and monthly payment.

Simulate paying off multiple debts at once with the snowball (smallest balance first) or avalanche (highest interest first) strategy, and see exactly when you'll be debt-free.

The Debt-to-Income (DTI) Ratio Calculator computes your front-end and back-end debt percentages based on your gross income.

Use this down payment calculator to find your affordable home price from available cash, calculate exactly how much cash you need for a given home price, or determine your down payment percentage.

The FHA Loan Calculator helps estimate your monthly payment and total costs associated with FHA mortgages.

Use this HELOC calculator to estimate your draw period and repayment period monthly payments, total interest paid, and see a full amortization schedule for your Home Equity Line of Credit.

The Home Equity Loan Calculator helps you estimate monthly payments based on loan values, and discover your potential maximum borrowable home equity.

Estimate an affordable purchase amount for a house based on either household income-to-debt estimates or fixed monthly budgets.

Calculate your monthly loan payment, total interest, and full amortization schedule for any fixed-rate installment loan.

Free loan comparison calculator. Compare up to three loans by monthly payment, total interest, upfront fees, total cost and fee-inclusive APR to see which offer is really cheapest.

The Mortgage Calculator helps estimate the monthly payment due along with other financial costs associated with mortgages.

Evaluate how adding extra payments or bi-weekly payments can save on interest and shorten your mortgage term.

Free mortgage points calculator. See what discount points cost, your new rate and payment, how many months until they pay for themselves and the net gain over the years you keep the loan.

Estimate your personal loan monthly payment, net proceeds after origination fees, and total interest — great for debt consolidation planning.

Compare your existing loan against a refinanced loan to evaluate monthly payment reductions or lifetime savings.

Decide whether it makes more financial sense to rent or buy a home by comparing costs, appreciation, and investment returns over time.

The Rental Property Calculator evaluates the financial viability, cash flow, and potential return on investment (ROI) of real estate rentals over time.

Get a ballpark estimate of how much cash a reverse mortgage (HECM-style) could make available from your home equity, based on your age, home value, and an assumed interest rate.

Estimate your student loan monthly payment, total interest, and payoff timeline — including grace period interest capitalization.

Estimate your UK mortgage payment (repayment or interest-only), Stamp Duty Land Tax (SDLT), and total upfront cash needed for a first-time buyer or home mover.

The VA Mortgage Calculator helps estimate the specialized costs associated with a Veterans Affairs loan.

Project your 401(k) balance at retirement, including your employee contributions, employer match, and optional annual raises.

Project the future value of an annuity's accumulation phase from an optional lump sum, periodic contributions, and an annual growth rate.

Calculate the fixed monthly payout an insurance annuity can generate from a starting balance over a guaranteed fixed term.

Calculate the true cost of borrowing with the APR Calculator. Understand hidden fees and interest expenses for both general loans and mortgages.

Convert between APR and APY for any compounding frequency, from annual to daily and continuous. Add a deposit and a term to see the balance and interest you would earn. Free and exact.

Calculate the arithmetic mean and the geometric mean (annualized/CAGR) return for a series of up to five periodic percentage returns, and see how much volatility drag matters.

Bond present value calculator: solve for price, yield, coupon, or maturity, plus clean/dirty price and accrued interest.

Estimate the federal tax owed on an investment or asset sale, based on your holding period, filing status, and taxable income -- covers both short-term and long-term capital gains.

Calculate the final balance and total interest earned on a Certificate of Deposit (CD). Supports all compounding frequencies and marginal tax adjustments for accurate projections.

Project the total future cost of college and calculate the monthly savings needed to close the gap between your current savings and that cost.

Calculate the estimated future value of your savings or investments with compound interest. Plan your wealth growth with our interactive financial tool.

Project dividend income, yield on cost and portfolio value over the years, with dividend growth, share price growth and an optional dividend reinvestment plan (DRIP). Year-by-year table included. Free.

Project the future value of investing a fixed amount on a regular schedule, and see how it compares to investing the same total as a lump sum today.

The Finance Calculator acts as a Time Value of Money (TVM) solver to calculate Future Value (FV), Periodic Payment (PMT), Interest Rate (I/Y), Number of Periods (N), or Present Value (PV).

Find your financial independence (FI) number from your spending and withdrawal rate, how many years until you reach it, your projected balance at retirement age and your Coast FIRE number. Free and private.

Calculate simple and compound interest with additional contributions, tax considerations, and inflation adjustments.

Accurately determine the real interest rate on loans when only the monthly payment and total price are provided.

The Investment Calculator can help determine one of many different variables concerning investments with a fixed rate of return. Solve for End Amount, Additional Contribution, Return Rate, Starting Amount, or Investment Length.

Project your Traditional IRA balance at retirement, plus this year's tax deduction and the after-tax value of your balance at withdrawal.

Calculate the internal rate of return (IRR) for an initial investment followed by a series of periodic cash flows, plus the NPV at a comparison discount rate.

Calculate the required margin, maximum buying power, and whether your account equity is sufficient to open a leveraged trading position.

Project a mutual fund's future value net of its expense ratio and front-load or back-load sales fees, and see exactly how much those fees cost you over time.

Calculate how many years it takes to recover an initial investment from a series of periodic cash inflows, using the cumulative-cash-flow method with fractional-year interpolation.

Estimate your defined-benefit pension payout from your years of service, accrual rate, and final average salary, including any early-retirement reduction.

Simulate how long a self-managed retirement portfolio will last given your withdrawal amount, expected return, and optional inflation adjustment.

Calculate your Required Minimum Distribution (RMD) using the IRS Uniform Lifetime Table, based on your account balance and current age.

Calculate the total return on investment (ROI) and annualized ROI from a known cost and final value -- no assumed rate of return required.

Project your Roth IRA balance at retirement -- fully tax-free, since Roth contributions are made with after-tax dollars.

Estimate how many years it takes an investment to double, triple, or quadruple at a given annual return -- or find the rate you'd need to double your money in a target number of years.

Estimate the end balance and interest of your savings accounts, considering factors like tax, inflation, and periodic contributions.

Free simple interest calculator using I = Prt. Find interest earned, final balance, or solve for rate on loans and investments instantly.

Estimate your Social Security Primary Insurance Amount from your average indexed monthly earnings, and see how claiming early or late changes your benefit.

Calculate profit or loss on a stock trade including buy and sell fees, return percentage, break-even sell price, tax on gains and the sell price needed for a target return. Free and private.

Find your break-even point in units and sales from fixed costs, variable cost per unit and price. Add a target profit to see the sales you need, and expected sales for your margin of safety. Free.

Compare your actual spending against the 50/30/20 budgeting rule (or your own custom percentages) across needs, wants, and savings, with a variance breakdown for each category.

Calculate sales commission on a flat percentage rate or a progressive tiered rate structure, plus your On-Target-Earnings total when a base salary is added.

Free credit utilization calculator. Enter balances and limits for up to five credit cards to see your utilization ratio per card and overall, and how much to pay down to reach a target like 10% or 30%.

Calculate asset depreciation using the Straight-Line, Declining Balance, or Sum-of-Years-Digits method, with a full year-by-year depreciation schedule.

Calculate the final sale price and total savings from one or two stacked percent-off discounts, or work backward from a known sale price to find the original price.

Work out how much your emergency fund should be from your monthly essential expenses and months of cover, then see how long it takes to save with your monthly contribution and interest. Free.

Estimate federal estate tax owed using a simplified flat top-rate approximation -- gross estate value, prior taxable gifts, and the current federal exemption.

Work backward from your target annual income, time off, business expenses, and a tax reserve to the hourly rate you actually need to charge as a freelancer.

Estimate your total federal income tax liability for the year -- taxable income, marginal rate, effective rate, and total tax owed -- using the current tax brackets and standard deduction.

Calculate how inflation changes the value of money over time -- project how much future money you'll need to match today's purchasing power, or discount a future amount back into today's dollars.

Calculate markup and margin from any two of cost, selling price, profit, markup percentage or margin percentage. Know the difference between markup and margin and price products correctly. Free.

Find out whether filing Married Filing Jointly saves you money (a marriage bonus) or costs you money (a marriage penalty) compared to each spouse's tax bill as a single filer.

Calculate your net worth by adding up your assets -- cash, investments, retirement accounts, real estate -- and subtracting your liabilities.

Calculate gross pay including overtime at time-and-a-half or any multiplier, with optional double time after a second threshold. See regular, overtime and double-time pay and your effective hourly rate.

Calculate a pay raise from a percentage, a dollar amount or the new pay. See the new salary, raise amount and percent, hourly equivalent, and your pay after several years of the same raise.

Estimate your take-home pay per paycheck and per year, including federal income tax, Social Security, Medicare, pre-tax 401(k)/HSA contributions, and a flat state tax estimate.

Estimate the affordable monthly rental spending amount based on your income and existing debt levels.

Free rent split calculator for roommates. Divide rent equally, by bedroom size, by income, or with common areas shared equally and bedrooms by size, with shares that add up exactly to the rent.

Convert gross pay between hourly, daily, weekly, biweekly, semimonthly, monthly and annual. Adjust hours per week and paid weeks per year. Free, instant and private.

Calculate US sales tax added at the register -- add tax to a pre-tax price, or back out the pre-tax price and tax amount from a known total.

Free US self-employment tax calculator for 2025 and 2026. Estimate Social Security and Medicare tax on freelance or business profit, the Additional Medicare Tax, the deductible half and quarterly payments.

Generate accurate weekly time reports with our easy-to-use time card calculator. Support for breaks, rounding, and overtime.

Free unit price calculator. Compare up to four products of different sizes and units (grams, kilos, ounces, pounds, millilitres, litres, fluid ounces or items) to find the cheapest price per kg, lb, litre or unit.

Calculate Value Added Tax (VAT) -- add VAT to a net price to get the gross price, or back out the net price and VAT amount from a VAT-inclusive gross price.

Estimate your body fat percentage using the U.S. Army circumference-based tape-test method (AR 600-9) and compare against Army standards by age band.

Calculate your Body Mass Index (BMI) and understand your health status with our interactive tool.

Calculate your body fat percentage, body fat mass, and lean body mass using the U.S. Navy Method and BMI Method. Plan your fitness journey with our interactive tool.

Calculate your Body Surface Area (BSA) using the Mosteller and DuBois formulas from your height and weight.

Estimate your body type (ectomorph, mesomorph, or endomorph) using the wrist-circumference-to-height frame-size ratio.

Calculate your fat-free mass index (FFMI) and height-normalised FFMI from weight, height and body fat percentage, with lean and fat mass. Metric and imperial units. Free, private, for information only.

Calculate your healthy weight range based on your height using the WHO healthy BMI band (18.5-25).

Free ideal weight calculator using Hamwi, Devine, Robinson & Miller formulas. Get your ideal body weight by height, age, and sex in seconds.

Calculate your lean body mass (fat-free mass) using the Boer, James, and Hume formulas from just your height, weight, and sex.

Calculate how much excess weight you're carrying above the healthy BMI ceiling, plus a realistic safe weight-loss timeline.

Calculate your waist-to-height ratio and see which health-risk band it falls in, with your target waist for a ratio of 0.5. Metric and imperial units. Free, private, and for information only.

Calculate your waist-to-hip ratio (WHR) from two tape-measure readings and see how it compares to WHO health-risk categories for your sex.

Free alcohol units calculator. Add your usual drinks to see UK alcohol units, US standard drinks, grams of pure alcohol and calories per week, compared with the 14-unit low-risk guideline.

Calculate your Basal Metabolic Rate (BMR) using the Mifflin-St Jeor, Revised Harris-Benedict, and Katch-McArdle formulas.

Add your coffee, tea, energy drinks and more to total your daily caffeine, compare it with a healthy limit and see how much is still in your body at bedtime and when it drops below your sleep cut-off. Free and private.

Estimate your daily calorie needs using science-backed BMR equations. Plan weight loss, maintenance, or gain with our interactive calorie calculator.

Work out the daily calorie deficit and calorie target for your weight-loss pace, how many weeks it takes and your estimated goal date, with warnings for fast paces or very low calories. kg and lb. Free and private.

Calculate calories burned during exercise using MET (Metabolic Equivalent of Task) values for common activities.

Free cal to joule converter. Instantly convert calorie to joule, kcal to kJ, and food Calories to kilojoules with exact 4.184 factor.

Calculate your recommended daily carbohydrate intake in grams based on your calorie needs and the Acceptable Macronutrient Distribution Range.

Calculate your recommended daily water intake based on your weight and activity level.

Calculate your recommended daily fat intake in grams based on your calorie needs and the Acceptable Macronutrient Distribution Range.

Calculate your daily protein, carbohydrate, and fat targets in grams based on your calorie needs and macro split preference.

Calculate your recommended daily protein intake in grams based on your body weight, activity level, and goal.

Calculate your Total Daily Energy Expenditure (TDEE) using the Mifflin-St Jeor BMR equation and an activity-multiplier breakdown.

Estimate your one-rep max (1RM) from a submaximal set using the Epley and Brzycki formulas, plus a training percentage table.

Estimate pace, time, and distance for running, walking, or biking. Includes multipoint calculations, converters, and finish time predictions.

Convert a daily step count into an estimated distance walked and calories burned, based on your height and weight.

Calculate your target heart rate training zone using the Karvonen method, based on your age and resting heart rate.

Estimate your VO2 max (aerobic fitness) from your age and resting heart rate using the Uth-Sorensen-Overgaard-Pedersen non-exercise formula.

Calculate your Wilks and DOTS powerlifting scores from body weight, sex and total lifted, in kg or lb, and see the coefficients used. Compare lifters of different sizes fairly. Free and private.

Estimate the likely conception date range from a known due date or birth date, using the reverse of Naegele's Rule.

Calculate your estimated due date from your last period, conception date, IVF transfer date, or an ultrasound scan.

Free hCG doubling time calculator. Enter two beta-hCG blood test results and the hours or days between them to get the doubling time and the percentage rise per 48 hours.

Predict your ovulation day and fertile window for your next few cycles based on your last period and average cycle length.

Predict your next several menstrual period start and end dates based on your last period and average cycle length.

Calculate your due date, current gestational age, and trimester milestones from your last menstrual period.

Calculate your recommended total pregnancy weight gain range and weekly gain rate based on your pre-pregnancy BMI, using IOM guidelines.

Convert between A1C percentage and estimated average glucose (eAG), in mg/dL or mmol/L, using the ADAG study formula -- works in both directions.

Estimate your blood alcohol concentration (BAC) using the Widmark formula. Informational only — not a breathalyzer substitute.

Enter a systolic and diastolic reading to see which American Heart Association blood pressure category it falls into -- Normal, Elevated, Hypertension Stage 1 or 2, or Hypertensive Crisis.

Calculate your total cholesterol to HDL ratio, non-HDL cholesterol and LDL to HDL ratio, with an LDL estimate from triglycerides. Works in mg/dL and mmol/L. Free, private, for information only.

Estimate creatinine clearance (mL/min) with the Cockcroft-Gault equation from age, sex, weight and serum creatinine, using actual, ideal or adjusted body weight. Metric and US units. For information only, not medical advice.

Estimate your kidney function using the race-free CKD-EPI 2021 creatinine equation for glomerular filtration rate (eGFR).

Free IV flow rate calculator for nursing students and clinicians. Work out the infusion rate in mL/h and the gravity drip rate in drops per minute from volume, time and drop factor, or the infusion time from a rate.

Calculate mean arterial pressure (MAP) and pulse pressure from systolic and diastolic blood pressure, and see whether MAP falls in the usual 70 to 100 mmHg range. Free, private, for information only.

Calculate pack-years from cigarettes per day and years smoked, across one or several periods, and see whether you meet the US criteria for annual lung cancer screening. Free, private, for information only.

Free QTc calculator. Correct the QT interval for heart rate with the Bazett, Fridericia, Framingham and Hodges formulas, from heart rate or RR interval, with sex-specific reference ranges.

A free online basic calculator with a full on-screen keypad — addition, subtraction, multiplication, division, percent, parentheses, memory (M+/M-/MR/MC), and a running calculation history.

A free online big number calculator for exact arbitrary-precision arithmetic (add, subtract, multiply, divide, exponentiation) on integers far beyond JavaScript's safe-integer range, powered by native BigInt.

Convert decimals to fractions and fractions to decimals exactly, including repeating decimals like 0.(3) = 1/3. Get the reduced fraction, mixed number and the closest simple fraction. Free.

A comprehensive fraction calculator for addition, subtraction, multiplication, division, simplification, and conversions.

A free online long division calculator that shows the quotient, remainder, and a full step-by-step long division work grid — with an option to continue dividing into decimal places instead of stopping at the remainder.

Free percent error calculator. Find the percent, signed, and absolute error between an experimental (measured) value and a theoretical (accepted) value.

A free online percentage calculator with four modes: X% of Y, X is what % of Y, percent increase/decrease from X to Y, and X plus or minus Y%.

A free online ratio calculator that simplifies a ratio to lowest terms, solves a proportion for a missing term, and scales a ratio by a factor or to a target total.

A free online rounding calculator that rounds any number to a chosen number of decimal places or to the nearest ten, hundred, or thousand, with five rounding modes: half up, half down, ceiling, floor, and half to even.

A free online scientific calculator with trigonometry (sin, cos, tan), degrees/radians toggle, logarithms, powers, roots, factorial, π and e constants, parentheses, and memory keys.

Count the significant figures in any number and round to a chosen number of sig figs. Handles leading and trailing zeros, decimal points and scientific notation. Free and exact.

A free online binary calculator for arithmetic (add, subtract, multiply, divide) and bitwise (AND, OR, XOR, NOT, shift) operations on binary numbers, with the decimal equivalent shown alongside every result.

Free complex number calculator. Add, subtract, multiply and divide complex numbers, raise to a power, find all n-th roots, and convert between rectangular, polar and exponential form with modulus and argument.

Free derivative calculator. Differentiate polynomials, trigonometric, exponential and logarithmic functions symbolically, get the second and third derivative, the value at a point and the tangent line.

A free online exponent calculator that computes b^n for integer, decimal, and negative exponents, and shows the expanded multiplication form for small integer exponents.

A free online factor calculator that lists every factor (divisor) of a positive integer, along with its factor pairs — and tells you instantly whether the number is prime or composite.

Calculate the exact factorial n! for any whole number up to 10,000. Also shows the number of digits, trailing zeros, scientific notation and the double factorial n!!. Free and instant.

A free online Greatest Common Factor (GCF / GCD) calculator for two or more numbers, showing the full Euclidean algorithm trace as step-by-step work.

Free online graphing calculator. Plot up to three functions of x, pan and zoom the graph, and get the roots, y-intercepts, intersections and a table of values. Runs in your browser.

Free half-life calculator for radioactive/exponential decay. Solve for remaining quantity, initial quantity, elapsed time, or half-life itself using N = N0 * (1/2)^(t / half-life).

A free online hexadecimal calculator for arithmetic (add, subtract, multiply, divide) and bitwise (AND, OR, XOR, NOT, shift) operations on hex numbers, with the decimal equivalent shown alongside every result.

A free online Least Common Multiple (LCM) calculator for two or more numbers, showing the full prime factorization method as step-by-step work.

A free online logarithm calculator that finds log base b of x, with dedicated common log (base 10) and natural log (base e) shortcuts, showing the full change-of-base work.

A free online matrix calculator for addition, subtraction, and multiplication of two matrices, plus determinant, inverse, and transpose of a single matrix, with a dynamically sized grid up to 4x4.

Calculate a mod n with negative numbers and decimals, and see truncated, floored and Euclidean remainders side by side. Also modular exponentiation (aᵇ mod n) and modular inverse. Exact and free.

Free number sequence calculator. Solve for the nth term and sum of an arithmetic or geometric sequence, or auto-detect the sequence type and constant from a list of terms.

Free polynomial root solver for cubic, quartic, quintic and sextic equations. Finds every real and complex root, shows repeated roots and gives exact values for rational roots.

A free online prime factorization calculator that breaks any whole number down into its prime factors, shown both as a step-by-step factor list and in compact exponent notation (e.g. 360 = 2³ × 3² × 5).

Check whether a number is prime, get its full prime factorization, divisor count and sum, and find the next and previous prime. Or list all primes in a range. Handles very large numbers. Free.

A free online quadratic formula calculator that solves ax² + bx + c = 0, showing the discriminant, root classification, real or complex roots, vertex, and axis of symmetry.

Free random number generator. Generate a list of cryptographically random integers or decimals within a custom min/max range, with options for unique values and sort order.

A free online root calculator for square roots, cube roots, and arbitrary nth roots — handles negative numbers correctly under odd roots and shows simplified radical form for square roots of positive integers.

A free online scientific notation calculator that converts standard numbers to and from scientific notation, and performs addition, subtraction, multiplication, and division on numbers already in scientific notation.

Solve systems of linear equations with 2, 3 or 4 unknowns. Get exact fraction answers, the determinant, and a clear verdict of one solution, no solution, or infinitely many. Free.

A free, quick-use area calculator for 7 common 2D shapes — square, rectangle, triangle, circle, trapezoid, parallelogram, and ellipse. One simple formula per shape; for a deep, dedicated circle solver, use the Circle Calculator instead.

A free, deep circle calculator that derives radius, diameter, circumference, and area from any one known value, plus a bonus arc length and sector area solver for a given central angle.

Free coordinate converter. Convert between Cartesian and polar coordinates in 2D, and between Cartesian, cylindrical and spherical coordinates in 3D, with angles in degrees or radians.

Free distance calculator. Find the distance between two points in 2D or 3D space, plus the midpoint for 2D coordinates, using the Pythagorean-derived distance formula.

A free online Pythagorean theorem calculator that solves for a missing leg or hypotenuse of a right triangle given the other two sides, using a² + b² = c².

A free online right triangle calculator that solves every side (a, b, c), both acute angles, area, and perimeter from any two known values — a fuller solver than a basic Pythagorean theorem calculator.

A free online slope calculator that finds the slope, slope-intercept equation, distance, and midpoint between two points on a coordinate plane.

Free online surface area calculator for cubes, rectangular prisms, spheres, cylinders, and cones. Enter your dimensions to instantly find the total surface area.

A free online triangle calculator that solves any general (non-right) triangle from SSS, SAS, ASA, or AAS inputs using the Law of Cosines, Law of Sines, and Heron's formula.

Calculate sin, cos, tan, csc, sec and cot for any angle in degrees, radians or gradians, see exact values like √3/2 at 30° multiples, and find angles with asin, acos and atan. Free.

Calculate the sum, difference, dot product, cross product, magnitudes, unit vectors, angle and projection of two 2D or 3D vectors. Detects perpendicular and parallel vectors. Free.

Free online volume calculator for cubes, rectangular prisms, spheres, cylinders, and cones. Enter your dimensions to instantly find the total volume.

A free online average calculator that finds the mean, sum, count, minimum, and maximum of a variable-length list of numbers — add or remove rows as needed.

Calculate binomial probabilities: exactly k successes, at most, fewer than, at least or more than k, and a range. Also mean, variance, standard deviation and a bar chart. Accurate for n up to 100,000. Free.

Free chi-square calculator. Run a goodness-of-fit test against equal or expected frequencies, or a test of independence on a contingency table, with the chi-square statistic, p-value, critical value, Cramér's V and expected counts.

Free confidence interval calculator for a population mean, using sample mean, sample standard deviation, sample size, and a 90%, 95%, or 99% confidence level with standard z-critical values.

Paste x and y data to get the least-squares regression line, slope, intercept, correlation r, R², standard errors and predictions, with a scatter plot of the fit. Free and private.

Free calculator that finds the mean, median, mode(s), range, sum, and count of a variable-length list of numbers — handles no-mode and multi-modal data sets automatically.

Free p-value calculator. Compute a p-value from a z-score or a t-score (with degrees of freedom), one-tailed or two-tailed, using the standard normal and Student's t distributions.

Free permutation (nPr) and combination (nCr) calculator with the full factorial-based formula breakdown, guarding against r > n, negative inputs, and non-integers.

Free Poisson distribution calculator. Enter the average rate λ and a count k to get P(X = k), P(X ≤ k), P(X ≥ k), range probabilities, the mean, standard deviation and a probability chart.

Free probability calculator for single events, two independent events (AND/OR), complements, and combinatorial (n choose k) probability without replacement.

Free sample size calculator for surveys and studies. Find the required sample size from a confidence level, margin of error, and an estimated proportion or standard deviation, with optional finite population correction.

Free standard deviation calculator that finds population and sample standard deviation and variance from a variable-length list of numbers, with a step-by-step deviation-squared breakdown.

Free all-in-one statistics calculator: mean, median, mode, range, variance, standard deviation (population & sample), quartiles, IQR, sum, count, min, and max from a single list of numbers.

Run a one-sample, two-sample (Welch or pooled) or paired t-test on your data. Get the t statistic, degrees of freedom, exact p-value, confidence interval, effect size and a plain-English decision. Free.

Calculate a weighted average from any number of values and weights, see each item's share and contribution, and find what score the next item needs to reach a target average. Free.

Free z-score calculator: find z from a value, mean, and standard deviation, solve for x in reverse, and get the percentile/area under the standard normal curve.

Calculate your exact chronological age from any birth date. Get a precise breakdown in years, months, and days — with leap-year handling, future date projections, and no sign-up required.

Find the number of years, months, weeks, and days between dates, or add/subtract time from a specific date.

Calculate your Semester and Cumulative GPA easily with our interactive tool. Plan your future grades and reach your academic goals.

Free grade calculator: find your weighted course grade and the score you need on your final exam to hit any target grade.

Add or subtract time values, compute time offsets from dates, and parse complex time expressions.

Calculate how long a file transfer will take based on file size, connection speed, and protocol overhead — or find the bandwidth needed to hit a target time.

Professional IPv4 subnet calculator for network administrators. Calculate network addresses, broadcast addresses, usable host ranges, and CIDR masks with ease.

Professional IPv6 subnet calculator. Plan your 128-bit network architecture, calculate prefix boundaries, and handle IPv6 address compression and expansion with ease.

Calculate usable capacity, space efficiency and the number of drive failures survived for RAID 0, 1, 5, 6, 10, 50, 60, ZFS RAID-Z and JBOD, with hot spares and TB or TiB display. Free.

Free SLA uptime calculator. Convert an availability percentage such as 99.9% or 99.99% into allowed downtime per day, week, month, quarter and year, work back from downtime to uptime, and combine components in series or parallel.

Plan a VLSM subnet layout: give a network and the hosts each subnet needs, and get the CIDR block, mask, usable range and broadcast address for each, largest first, with free space left. Free.

Calculate board feet for lumber from thickness, width, length and quantity across several boards, with total cost at a price per board foot and the equivalent in cubic metres. Free and private.

Estimate the cooling or heating needs of your room or house with our BTU calculator. Calculate exact requirements based on size, insulation, and climate.

Estimate the volume and weight of concrete needed for slabs, columns, stairs, and more. Get precise bag counts and truck delivery estimates.

Calculate the drywall sheets, screws, joint tape and joint compound for a room from its length, width and ceiling height, less doors and windows, with a waste allowance. Metric and imperial. Free.

Work out how many posts, sections, rails and pickets a fence needs from its length, post spacing, gates and board width, in metric or imperial. Use it to plan and price a fencing job. Free.

Calculate flooring for one or more rooms: total area, a waste allowance, how many packs or boxes to buy, what is left over and the cost. Works for laminate, vinyl, hardwood and tile in metric or imperial. Free.

Calculate how much gravel you need for a driveway or path in cubic yards, cubic feet, and tons.

Add up the R-values of your wall or ceiling assembly's layers to find its total R-value, then estimate heat loss for a given area and temperature difference.

Calculate how much mulch you need for your garden beds in cubic yards, cubic feet, and standard 2 cu ft bags.

Calculate how many gallons of paint you need for a room based on its dimensions, number of coats, and paint coverage per gallon.

Calculate how many gallons your pool holds from its dimensions -- supports rectangular and circular/round pools.

Convert roof pitch (like 6:12), angle in degrees and percent slope in any direction, then get rafter length with overhang, ridge height and roof surface area from your plan area. Metric and imperial. Free.

Accurately estimate your total roof area and the necessary amount of materials needed, including roofing squares, bundles of shingles, and recommended overage.

Accurately estimate the square footage and total cost of materials for a variety of common shapes, including rectangles, circles, triangles, and more.

Accurately calculate the exact dimensions for stairs including total run, stringer length, number of steps, and angle of inclination.

Estimate the total number of tiles necessary to cover a floor, roof, or wall, including calculations for grout gaps, overlaps, and total box costs.

Project a car's value year by year with a bigger first-year drop, or work out the average yearly depreciation rate from its price and current value. Free.

Estimate the cost of charging your electric vehicle from your battery size, charge level, and electricity rate -- and compare the cost per mile against a gas car.

Estimate the fuel needed and total cost for a trip based on distance, fuel efficiency, and price per gallon or liter.

Calculate your vehicle's fuel efficiency (MPG or L/100km) from the distance traveled and fuel used, plus your cost per mile or kilometer.

Estimate engine horsepower two ways — from quarter-mile trap speed and vehicle weight, or from torque and engine RPM.

Calculate your mileage reimbursement or tax deduction using the standard mileage rate for business, medical, moving, or charitable driving.

Calculate speed from distance and time, with instant results in mph, km/h, m/s, and knots.

Compare two tire sizes (e.g. 225/50R17) to see the difference in diameter, circumference, revolutions per mile, and speedometer accuracy.

Estimate battery runtime from capacity (mAh, Ah or Wh), load (mA, A or W), usable capacity and an active/sleep duty cycle, with average current and days of life. Free.

Calculate density from mass and volume, with instant results in kg/m³, g/cm³, and lb/ft³.

Free dilution calculator using C1V1 = C2V2. Find the stock volume, final volume or concentrations in M, mM, mg/mL or %, see how much diluent to add, and plan serial dilutions.

Free electrical power calculator. Convert between watts, volts and amps for DC, single-phase and three-phase AC, with power factor, apparent and reactive power, resistance and horsepower.

Estimate the energy consumption and running cost of any electrical appliance based on its wattage, daily usage, and your electricity rate.

Free ideal gas law calculator. Solve PV = nRT for pressure, volume, amount of gas or temperature with units such as atm, kPa, bar, psi, litres, moles, Celsius and Kelvin.

Calculate the series resistor for one or more LEDs from supply voltage, forward voltage and current, rounded up to a standard E24 or E12 value, with actual current and resistor power rating. Free.

Convert mass between milligrams, grams, kilograms, metric tons, ounces, pounds, stone, and US tons instantly.

Calculate the molarity of a solution from solute mass, molar mass, and solution volume — a core calculation for chemistry lab work.

Calculate the molecular weight (molar mass) of any chemical formula, including compounds with parentheses like Ca(OH)2.

Solve for voltage, current, resistance, or power using Ohm's Law — enter any two known values and calculate the rest.

Free projectile motion calculator. Enter launch speed, angle and height to get the range, maximum height, time of flight, impact speed and the best launch angle, with a drawn trajectory. Earth, Moon, Mars or Jupiter gravity.

Decode 4-band or 5-band resistor color codes into resistance value and tolerance, instantly and accurately.

Estimate how many years it takes for a home solar panel system to pay for itself through electricity bill savings, and project 25-year lifetime savings.

Calculate the output of a resistor voltage divider from Vin, R1 and R2, or solve for the missing resistor for a target Vout and pick the nearest standard E24 or E12 value. Shows current and power. Free.

Calculate voltage drop and percentage drop across a wire run based on wire gauge, material, distance, current, and circuit voltage.

Convert weight between kilograms and pounds, and see what you'd weigh on the Moon, Mars, Jupiter, and other planets based on their gravity.

Find the smallest AWG copper or aluminium wire for a load current, run length and allowed voltage drop, with the actual drop, heat loss and current rating. Metric or imperial. Free.

Calculate the dew point from air temperature and relative humidity using the Magnus formula, and see how muggy it will actually feel.

Calculate the heat index — the "feels like" temperature from air temperature and relative humidity — using the NWS Rothfusz regression.

Find the Moon's phase, percentage illuminated and age for any date and time, with a picture of the Moon and the dates of the next new moon, first quarter, full moon and last quarter. Free.

Calculate sunrise, sunset, solar noon, day length and civil, nautical and astronomical twilight for any date and location using NOAA solar equations, in your chosen time zone. Free.

Calculate wind chill — the "feels like" temperature from wind speed and air temperature — using the official NWS formula.

Count the number of days between two dates or calculate a future/past date. Includes options for business days, weekends, and holidays.

Find the day of the week for any historical or future date. Discover fascinating trivia and facts about every day of the week.

Free hours calculator to find the exact number of hours, minutes, and decimal hours between two times or dates. Instant calculation for timesheets, payroll, shifts, and schedules.

Free military time converter. Convert 12-hour AM/PM times to 24-hour and military time and back, with a full conversion chart from 0000 to 2300.

Find the best bedtime or wake-up time based on 90-minute sleep cycles, so you wake up feeling rested instead of groggy.

Calculate the exact time difference between two times or dates. Get results in hours, minutes, and seconds with our precise duration tool.

Convert time between different global time zones with our easy-to-use calculator. Understand UTC offsets, GMT, and daylight saving time.

Free week number calculator. Find the ISO 8601 week number of any date, the US week number, the day of the year and quarter, or list the Monday-to-Sunday dates of any ISO week.

Free baker's percentage calculator. Turn a bread or pizza formula into gram weights for any batch size, or turn your recipe weights into baker's percentages and hydration.

Free depth of field calculator for photographers. Enter focal length, aperture, subject distance and sensor size to get the near and far limits of sharp focus, total depth of field and hyperfocal distance.

Roll virtual dice online — choose the number of dice and sides (d4 to d100) and get instant results with the total.

Convert your dog's age to human years using the size-based chart, the epigenetic formula 16 ln(age) + 31 and the classic 7x rule, with the life stage for your dog's size. Free.

Free Female Delusion Calculator: estimate what share of U.S. men meet height, income, age-range, and BMI standards.

Calculate Gross Domestic Product (GDP) using the expenditure approach — consumption, investment, government spending, and net exports.

Calculate your golf score differential from your score, course rating, and slope rating — the building block of the USGA Handicap Index.

Convert height between feet and inches, centimeters, and meters instantly, in either direction.

Free Male Delusion Calculator: estimate the share of U.S. women meeting BMI, height, income, and age standards.

Free pizza size calculator. Compare up to four pizza sizes and prices by area and price per square inch or per 100 cm², find the best deal, and see how many small pizzas equal one large.

Free print size calculator. Convert between image pixels, DPI and print size in inches or centimetres, see the largest good-quality print and check standard sizes such as 4x6, 8x10, A4 and A3.

Paste a recipe's ingredients and scale them to a new number of servings, with fractions handled, units tidied (4 tsp becomes 1 1/3 tbsp) and optional US or metric conversion. Free.

Convert numbers to Roman numerals or Roman numerals back to numbers, instantly and accurately, for values from 1 to 3,999.

Find a screen's width, height and area from its diagonal and aspect ratio, or its diagonal and ratio from a width and height, plus pixel density (PPI) and dot pitch from the resolution. Free.

Convert shoe sizes between US Men's, US Women's, UK, EU, and foot length in centimeters — a handy reference for international shopping.

Calculate the tip amount, total bill, and per-person split for any bill amount and tip percentage.

Free video file size calculator. Work out how big a 1080p or 4K video will be from its bitrate and length, the bitrate needed to hit a file size, or how many minutes fit on a card, in MB, GB and GiB.