About the tone generator
This tone generator plays a pure tone at any frequency from 20 Hz to 20 kHz, with a choice of sine, square, triangle or sawtooth waveform and a volume control. Use it to test speakers and headphones, check your hearing range, tune instruments or generate reference tones. The sound is created with the Web Audio API in your browser.
How Tone Generator works
How to play a tone
- Set the frequency with the slider or by typing a value in Hz.
- Choose a waveform and a comfortable volume.
- Press Play; press Stop to silence it.
Frequencies and waveforms
A sine wave is the purest tone; square, triangle and sawtooth waves sound harsher and richer. Human hearing typically spans about 20 Hz to 20 kHz, declining at the top with age.
Protect your ears and gear
Start at a low volume — high-amplitude tones, especially at very low or very high frequencies, can damage speakers and hearing.
Common uses
- Test speakers and headphones
- Check your hearing range
- Tune an instrument to a reference pitch
- Generate a reference tone
- Find a speaker buzz or rattle
- Demonstrate frequencies and waveforms
- Calibrate audio equipment
- Create a steady test signal
Frequently asked questions
How do I generate a tone?
Set a frequency, choose a waveform and volume, then press Play.
What frequency range can it play?
From 20 Hz to 20 kHz — roughly the range of human hearing.
What is the difference between the waveforms?
Sine is the purest; square, triangle and sawtooth add harmonics and sound harsher.
Can I test my hearing?
Yes — raise the frequency until you can no longer hear it (do so at low volume).
Why press Play before I hear sound?
Browsers require a click to start audio.
Is anything uploaded?
No — the tone is generated in your browser.
Can it damage my speakers?
High volumes can — start low, especially at extreme frequencies.
Is it free?
Yes — completely free with no sign-up.