Tone generator. Any frequency from 20 Hz to 20 kHz, in your browser.

Questions

What can I use a tone generator for?

Testing speakers and subwoofers, finding a rattle or a room resonance, checking the range of your headphones or your hearing, tuning an instrument to a reference pitch, and audio experiments in class.

Why can't I hear the highest frequencies?

Most adults stop hearing somewhere between 12 and 17 kHz, and the limit falls with age. Many laptop and phone speakers also can't reproduce very low or very high tones, so silence there may be the speaker, not your ears.

What's the difference between the waveforms?

A sine is a single pure frequency. Square, sawtooth and triangle waves add harmonics above it: a square and a triangle only odd ones, a sawtooth every one, so they sound brighter and buzzier at the same pitch.

Is it safe?

Keep the level low and listen briefly. The tool starts at a quiet level and warns when you raise it; turn your device volume down before you start, especially with headphones.

Is it free?

Yes, with no sign-up. The tone is generated in your browser; nothing is recorded or sent anywhere.