Online Tone Generator
Play any frequency from 20 Hz to 20,000 Hz, in the waveform and the ear you choose. It runs in this page — nothing to install, nothing uploaded.
A4 · standard concert pitch
Start with the volume low, especially on headphones. High frequencies are far louder than they sound at first.
Presets
Need more than one tone?
Frequency Generator plays several frequencies at once, sweeps the whole range, and adds binaural beats, DTMF tones and musical note presets — with no browser tab to keep open.
What a tone generator is for
A tone generator plays one exact frequency instead of music. That sounds abstract until you need it, and then nothing else will do: a single, unchanging tone is the only way to hear what a speaker, a room or an ear does to one specific part of the audible range.
The usual reasons people open one:
- Testing speakers and headphones. Sweep down through the bass to find where the low end stops, or hold a tone that makes a driver rattle to confirm something is loose.
- Tuning an instrument. 440 Hz is concert A. The readout names the nearest note and shows how far off you are in cents, so you can tune to any pitch, not just A.
- Checking your hearing. Most people stop hearing somewhere between 14,000 and 17,000 Hz, and that ceiling drops with age.
- Masking tinnitus. Some people find a tone close to the pitch they hear gives temporary relief. It is not treatment, and it does not work for everyone.
- Science and demonstrations. Standing waves, beat frequencies, resonance — all easier to show with a clean tone than to describe.
Sine, square, triangle, saw
A sine wave is a single frequency and nothing else — the reference for any kind of testing. A square wave adds every odd harmonic above the fundamental, which is why it sounds hard and hollow and measures far louder at the same volume setting. Asaw wave adds all harmonics and is brighter still. A trianglesits between sine and square. If you are testing equipment, use sine; the others are for sound design and for hearing what harmonics do.
A word on volume
Start quiet and come up slowly. High frequencies are perceived as much quieter than they measure, so it is easy to set a 15 kHz tone at a level you would never tolerate at 1 kHz. Sustained low frequencies at high volume are also the most reliable way to damage a small speaker. Neither risk is theoretical, and both are avoidable by starting at the bottom of the volume slider.
Questions
What frequency should I use to test a speaker?
Start at 1,000 Hz — it sits in the middle of hearing and every speaker should reproduce it cleanly. Then walk down towards 100 Hz and 50 Hz to hear where the bass gives out, and up towards 10,000 Hz for the treble. A speaker that buzzes or rattles at one specific frequency usually has something loose or damaged rather than a fault across the whole range.
Is 432 Hz really better than 440 Hz?
There is no measured evidence that it is. 440 Hz is the international standard for A4 and 432 Hz is a slightly flatter alternative that some musicians prefer the character of. Both presets are here because people look for both; nothing physical distinguishes them beyond pitch.
Can a tone generator damage my speakers or my hearing?
Yes, at high volume. Square and saw waves carry far more energy than a sine wave at the same setting, and sustained low frequencies are what usually kill small speakers. High frequencies are the hearing risk, because they feel quieter than they are. Start low, raise slowly, and never wear headphones while sweeping.
Why does a very high tone sound quiet or silent?
Two reasons, and they compound. Human hearing rolls off sharply above about 15,000 Hz and that ceiling falls with age. Phone and laptop speakers also stop reproducing much above roughly 15,000–16,000 Hz. If a tone disappears, try the same frequency on headphones before concluding anything about your ears — or use the hearing test, which is built for exactly this.
Does the frequency have to be a whole number?
No. Type any value in the box — 440.5 works. The readout shows the nearest musical note and how many cents sharp or flat you are, which is what makes this usable for tuning.
