Free Tone Generator — Test Tones & Frequencies Online
Need a clean test tone? This generator uses the Web Audio API to synthesize pure frequencies from deep 20 Hz sub-bass to the 20 kHz edge of human hearing, in sine, triangle, square, or sawtooth waves. Test speakers and headphones, tune instruments against A440, or check how high your hearing still reaches. No audio files, no downloads — the tone is generated live on your device.
Tone Generator
Pure tones from 20 Hz to 20,000 Hz — speaker tests, instrument tuning, and hearing checks, generated live in your browser.
1 Set your tone
2 Play & test
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How it works
When you press Play, the tool creates a Web Audio oscillator set to your frequency and waveform, routes it through a gain node (your volume control) to your speakers, and starts it. Moving the frequency or volume sliders adjusts the oscillator in real time. Press Stop and the oscillator is destroyed — nothing is recorded or stored.
Everyday uses
- Audio setup — sweep frequencies to find room rattles, dead speaker ranges, and subwoofer limits.
- Musicians — use A440 (or any reference pitch) to tune by ear.
- Hearing checks — see which high frequencies you can still hear (results vary by headphones and age).
- Science classes — demonstrate pitch, waveforms, and the limits of human hearing live.
Frequently asked questions
Why can’t I hear very low or high tones?
Human hearing runs roughly 20 Hz–20 kHz and narrows with age; small speakers also cannot reproduce deep bass. Use headphones for the extremes and keep volume modest.
Is the tone exactly the frequency shown?
Yes — the oscillator is set digitally, so 440 Hz is exactly 440 Hz, limited only by your device’s audio clock.
Can high tones damage speakers or ears?
At high volume, yes — especially tweeters and eardrums. Start quiet and raise volume slowly.