Online Tone Generator

A tone generator produces a pure, steady sound at a frequency you choose. That simple capability is surprisingly useful: audio engineers use reference tones to test and calibrate speakers and headphones; musicians use a fixed pitch (like 440 Hz, concert A) to tune instruments; and anyone can use a frequency sweep to check the range of their hearing or find the resonant buzz in a room or a rattling car panel.

Because the tone is generated mathematically rather than played from a file, it's perfectly clean and can hold any frequency indefinitely — something a recording can't do as precisely.

Human hearing spans roughly 20 Hz (a deep rumble you feel more than hear) to 20,000 Hz (a thin whistle most adults can no longer hear). This tool covers that range. Low frequencies test a speaker's bass response; very high ones reveal both your hearing limits and whether tiny tweeters are working.

The waveform shapes the character of the sound. A sine wave is the purest tone, a single frequency with no overtones — best for tuning and testing. Square, sawtooth and triangle waves add harmonics, giving a richer, buzzier sound useful for synth-style tones and for hearing how harmonics behave. The tone is synthesised live in your browser with the Web Audio API; nothing is recorded or uploaded.

Start with the volume low, especially at high frequencies and on headphones. A loud pure tone is more fatiguing and potentially more harmful to hearing than music at the same volume, because all its energy sits at one frequency. Raise the level gradually only as needed.

For a hearing self-check, play a sine wave and slowly increase the frequency: note where the tone becomes faint and where it disappears. This is a rough, fun indicator — not a medical test. If you're concerned about your hearing, see an audiologist for a proper audiogram.