Online Tone Generator
Free · No sign-up · Nothing is uploaded or recorded
Press Space to play or stop while focus is in this tool.
Start quiet. A tone can be much louder than it looks on speakers and headphones. Turn your own volume down first, then raise this slowly.
The highest frequency this browser can play, half its sample rate, is shown here after you press Play.
Speakers, headphones and your ears limit what you hear. Small speakers play very little at the lowest frequencies, and the highest ones may be quiet or silent even when the browser plays them.
What is a tone generator?
A tone generator is a tool that makes a steady sound at a frequency you choose, measured in hertz (Hz). This one builds the tone in your browser with the Web Audio API, from 20 Hz to 20 kHz. You pick the waveform, from a pure sine to a bright sawtooth, then set the pitch by frequency or by musical note. You can send it to the left or right speaker, or sweep it between two frequencies.
How it works
Step 1
Pick a sound
Choose a waveform, then set the frequency with the log slider, the number box or the fine steps. Or switch to Note and pick a note and octave.
Step 2
Keep the volume low
The volume starts low. Turn your own speakers or headphones down first, press Play, then raise the volume slowly.
Step 3
Play, or run a sweep
Play and Stop fade the sound in and out over a few milliseconds. A sweep glides from a start to an end frequency over the time you set. Choose left, right or both channels at any time.
Questions
Is any audio uploaded?
No. The tone is made by your browser's own audio engine as you listen. Nothing is recorded, downloaded or sent anywhere.
What is the highest frequency it can play?
The slider goes from 20 Hz to 20 kHz. A browser can only play up to half its sample rate, so after you press Play the page shows that limit for your device. If it is lower than 20 kHz, the slider stops there.
Why can I not hear the lowest or highest tones?
Speakers, headphones and ears all limit what you hear. Small speakers play very little at the lowest frequencies, and the highest tones may be quiet or silent on your equipment. The page sends the tone you set; it does not measure what comes out.
How does Note mode work?
Pick a note and an octave and the page plays its equal-temperament frequency. Each semitone is a factor of 2 to the power of 1/12, with A4 at 440 Hz unless you change the reference.
What is the difference between a linear and a logarithmic sweep?
A linear sweep moves the same number of Hz every second, so it spends most of its time in the high frequencies. A logarithmic sweep moves the same ratio every second, so each octave takes the same time.
Privacy: what runs where
- The tone is generated in this browser tab. No audio is uploaded, and the page never asks for your microphone.
- Sound stops when you press Stop, when a sweep ends, or when you leave the page.
- Sweeps run for 0.5 to 300 seconds, and nothing is downloaded from anywhere else: the generator is part of this page.