Creatinine Clearance Calculator - Cockcroft-Gault Estimate
Creatinine Clearance Calculator
Estimate kidney function with the Cockcroft-Gault equation
Classic Equation
The Cockcroft-Gault formula: (140 − age) × weight ÷ (72 × creatinine), multiplied by 0.85 for women.
Three Weight Options
Choose actual, ideal (Devine) or adjusted body weight, as different clinical guidance recommends for different body sizes.
Both Unit Systems
Enter creatinine in µmol/L or mg/dL and see it in both, with weight and height converted to match.
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What Creatinine Clearance Estimates
Creatinine is a waste product from muscle that healthy kidneys filter out of the blood. Creatinine clearance estimates how much blood the kidneys clear of it per minute, a rough measure of kidney function. The Cockcroft-Gault equation, published in 1976, was long used to adjust medicine doses. Today many labs and guidelines prefer eGFR equations for staging kidney disease, and this calculator is not the same as your lab's eGFR.
This is an estimate for adults, for information only. It is not a diagnosis and must not be used to choose or change a medicine dose. Results are less reliable in people with very low or high body weight, muscle loss, pregnancy, rapidly changing kidney function or acute illness. Ask your doctor or pharmacist to interpret your own kidney results.
Key Takeaways
- Adults only: Ages under 18 are rejected, as the equation is not designed for them.
- Clear limits: Explains why this is not the same as an eGFR and not a dosing tool.
- Information only: Not a diagnosis or medical advice.