Online Tone Generator - Sine, Square and Sawtooth Waves from 20 Hz to 20 kHz
Tone Generator
Play any frequency, sweep the audible range, test speakers
Four Waveforms
A pure sine for hearing and tuning, or square, sawtooth and triangle rich in harmonics.
Speaker and Headphone Check
Pan the tone left or right to confirm the channels are wired the right way round.
Musical Notes
See the nearest note and how many cents sharp or flat the frequency is, based on A4 = 440 Hz.
Generated Locally
Sound is synthesised in your browser with the Web Audio API; nothing is downloaded or recorded.
Using a Tone Generator
Young adults typically hear from about 20 Hz to 17-20 kHz, and the upper limit falls with age, so a slow sweep is a quick, informal check of your high-frequency hearing (it is not a medical hearing test). Low tones from 20 to 100 Hz test subwoofers and reveal rattles, and 50 or 60 Hz matches mains hum. Musicians use 440 Hz, the A above middle C, as the standard tuning reference.
Very high and very low frequencies can be hard to hear even when they are loud, so raise the volume carefully and stop if anything feels uncomfortable. Small laptop and phone speakers cannot reproduce deep bass; use headphones or proper speakers below about 100 Hz.
Key Takeaways
- Volume low first: Increase slowly, especially with headphones.
- Log slider: Each octave takes the same distance on the slider.
- Not a hearing test: See an audiologist for a proper assessment.