Tone generator
The tone is made in your browser. Nothing is uploaded.
440 Hz
Nearest note A4 · wavelength 78.0 cm
Start quietly, especially with headphones. ÷2 and ×2 move one octave.
How to use this tool
Play a pure tone at any frequency from 20 Hz to 20 kHz. Nothing is uploaded.
Open Tone generator
It is set to 440 Hz (A4), a sine wave, both speakers, at 20% volume. Press Play.
Set the frequency
Type a value, drag the slider, use ÷2/×2 for an octave or pick a preset such as 1000 Hz.
Change the sound
Pick a waveform and send the tone to the left, right or both speakers to test them one at a time.
FAQ
What can I use a tone generator for?
To test speakers and headphones, check left and right channels, find a rattle or hum, tune an instrument to A4 = 440 Hz, or try the range of your hearing.
Which waveform should I use?
Sine is a pure tone, best for tests. Square, triangle and sawtooth add harmonics and sound buzzier.
Why can't I hear very low or very high tones?
Small speakers rarely play below about 80 Hz, and hearing above 15–17 kHz fades with age. Your device's audio path may cut them too.
Is it safe for my ears and speakers?
Start at a low volume, especially with headphones and high frequencies. Volume starts at 20% for that reason. Stop if it hurts.
Does it work offline?
The tone is made in your browser with Web Audio; once the page has loaded, nothing else is downloaded or uploaded.