The short version
- Type a frequency or drag the slider, pick a waveform and press Play (or the space bar).
- A4 = 440 Hz is the standard tuning note. Middle C is 261.63 Hz. Every octave up doubles the frequency.
- Healthy young ears hear roughly 20 Hz to 20 kHz. The top end drops with age, which is normal.
- Test your speakers: Left, then Right, then a slow 20–200 Hz sweep to find where the bass gives up.
- Start quiet. Pure tones are more tiring than music at the same volume, especially in headphones.
- Share a tone with “Copy link”. It opens at the same frequency and waveform.
How to use the tone generator
- Turn your device volume down first. Seriously. Then press Play tone.
- Set the frequency by typing it in, dragging the slider, or tapping a preset. Use the nudge buttons for fine changes, and ½× / 2× to jump an octave.
- Choose a waveform. Sine is the pure tone. Square, saw and triangle add harmonics, so they sound buzzier. White and pink noise play every frequency at once.
- Pick a channel to send the sound to the left speaker, the right, or both.
- Run a sweep to glide smoothly from one frequency to another. A logarithmic sweep spends the same time on each octave, which is how we hear pitch.
- Copy the link to share exactly that tone with someone else.
Protect your ears (and your tweeters). Keep the volume low, especially with headphones and above 2 kHz, where our ears are most sensitive. Very low or very high tones you can’t hear can still be loud enough to damage speakers. If anything sounds painful or your ears ring, stop.
Which frequency should I use?
Here are the frequencies people look for most, and what they’re for. Every one is a preset above, or a quick type-in.
| Frequency | What it is | Use it for |
|---|---|---|
| 20–60 Hz | Sub-bass | Testing a subwoofer; you feel it as much as hear it |
| 50 / 60 Hz | Mains hum | Identifying hum in a recording (50 Hz in Europe, 60 Hz in North America) |
| 100 Hz | Bass punch | Checking small speakers and kick-drum weight |
| 261.63 Hz | Middle C (C4) | Music lessons, singing warm-ups |
| 440 Hz | A4, concert pitch | Tuning instruments, science class |
| 1,000 Hz | 1 kHz test tone | Setting levels in studios and broadcasting |
| 8,000 Hz | Sibilance range | Checking tweeters and headphone clarity |
| 15,000 Hz | High treble | A rough “how high can I hear?” check |
| 17,400 Hz | The “mosquito tone” | Proving to teenagers that you are, in fact, old |
Sine, square, sawtooth, triangle: what’s the difference?
A sine wave is a single, pure frequency. Every other waveform is the same fundamental plus a stack of harmonics (multiples of that frequency). The harmonics are what make them sound brighter and buzzier, and they are the raw ingredients of most synthesizer sounds.
| Waveform | Sounds like | Harmonics |
|---|---|---|
| Sine | A pure whistle or a tuning fork | None: just the fundamental |
| Triangle | Soft and flute-like | Odd harmonics, fading fast |
| Square | Hollow and retro, like an 8-bit game | Odd harmonics, fading slowly |
| Sawtooth | Bright and brassy; the classic synth lead | Every harmonic |
| White noise | Hiss, like TV static | Equal energy at every frequency |
| Pink noise | A deeper whoosh, like a waterfall | Equal energy in every octave |
Try this: play 110 Hz as a sine, then switch to square. Same note, completely different character. That’s why a flute and a trumpet playing the same pitch never sound alike.
How to test speakers and headphones
- Left and right check: pick Left, then Right. If the sound comes from the wrong side, your cables or headphones are swapped. Better to find out now than halfway through mixing.
- Bass extension: set a sweep from 20 to 200 Hz over 20 seconds, at low volume. The point where the tone appears is roughly where your speakers start producing bass.
- Rattles and buzzes: sweep slowly through 30–150 Hz. Anything in the room that vibrates (a loose panel, a picture frame, that one drawer) will announce itself.
- Room problems: walk around while playing a steady 60–100 Hz tone. Spots where it gets much louder or quieter are room modes. Moving your listening chair a little can help more than any plug-in.
- Pink noise for level matching: play pink noise and balance your speakers so they sound equally loud from your listening spot.
How high can you hear?
Healthy young ears hear from about 20 Hz to about 20,000 Hz. As we get older, the top end comes down gradually. It’s called presbycusis, it is completely normal, and it starts earlier than anyone would like. Try the 15 kHz and 17.4 kHz presets at a low volume. If you hear nothing, check that your speakers or headphones can actually play that high before blaming your ears: many small speakers can’t.
Want the proper step-by-step version with an “ear age”? Try the hearing test. Either way, this is a curiosity, not a medical test. If you are worried about your hearing, an audiologist can test it properly in a quiet booth with calibrated equipment.
432 Hz vs 440 Hz: does it matter?
The internet has strong feelings about 432 Hz. Here’s the calm version: 440 Hz has been the standard tuning reference since the mid-20th century, and 432 Hz is that same A tuned about 32 cents flat. Some people find it a touch warmer and more relaxing, which is perfectly valid. There’s no good evidence that it’s healthier or “in tune with the universe”, though. Play both presets and decide for yourself. If you like Solfeggio and meditation tones, my sister site Sacred Frequency has a whole set of them.
Why I built this
I'm a guitarist: a Cort, a lot of enthusiasm, roughly twelve notes. I bought a pair of studio monitors, plugged them in, and spent a week mixing before I noticed the left and right were swapped. A tone generator would have told me in four seconds. Most of the free ones I found were buried in pop-ups, or needed an app to make a beep.
So here is a clean one: type a number, hear a tone. I added the sweep after it found a rattling lampshade in my room at 87 Hz. The lampshade has since been moved. I also added pink noise because my mixes needed a reference, and white noise because my neighbour’s dog needed one.
How it works, and what it does with your data
Tones are generated live by the Web Audio API built into your browser: an oscillator for the four waveforms, and a looping buffer of random samples for the noise (filtered to make pink noise). Starts and stops fade in over about 10 milliseconds so they don’t click, and frequency changes glide rather than jump. The volume slider follows a curve that gives fine control at low levels and stops short of full scale.
Nothing is recorded or uploaded, and there’s no account. Your last frequency, waveform and volume are saved in your browser’s local storage, on your device only.
Tone generator FAQ
What is a tone generator?
A tone generator plays a single, steady frequency, such as 440 Hz. This one runs in your browser and can play sine, square, sawtooth and triangle waves from 1 Hz to 22,000 Hz, plus white and pink noise.
What frequency is the note A?
The A above middle C (A4) is 440 Hz in standard tuning. Each octave doubles the frequency, so A3 is 220 Hz and A5 is 880 Hz. Middle C is 261.63 Hz.
What is the range of human hearing?
Roughly 20 Hz to 20,000 Hz for young people with healthy ears. The top end drops with age: many adults hear little above 15–17 kHz, which is completely normal.
How do I test my speakers or headphones?
Play a tone in Left, then Right, to check the channels are the right way round. Then run a slow sweep from 20 Hz to 200 Hz at low volume to find where the bass fades out, and listen for rattles or buzzing.
What is the difference between white and pink noise?
White noise has equal energy at every frequency, so it sounds bright and hissy. Pink noise has equal energy in every octave, so it sounds deeper and more even, like a waterfall. Pink noise is used for setting up speakers; both are popular for sleep and focus.
Is 432 Hz better than 440 Hz?
There is no good evidence that 432 Hz is healthier or more natural. It is simply A tuned about 32 cents flat, which some people find warmer. Play both here and decide for yourself.
Can a tone generator help with tinnitus?
Some people use one to find the pitch of their tinnitus so they can describe it to an audiologist. It is not a treatment. If you have tinnitus or hearing loss, please see a doctor or audiologist, and keep the volume low.
Why can’t I hear very low frequencies?
Your speakers probably cannot reproduce them. Phone and laptop speakers typically roll off below 100–200 Hz. Headphones or a subwoofer go much lower. Switch to a square wave and you will hear its higher harmonics instead.
Can I share a specific tone?
Yes. Press “Copy link” and the link opens this page set to the same frequency and waveform, ready to play.
Does this work offline or upload anything?
Every sound is synthesised in your browser with the Web Audio API. Nothing is uploaded, there is no account, and once the page has loaded it keeps working without a connection.
Turning a tone into a track?
The free Paddy Prompt Studio builds Suno style prompts and Vidmuse video scripts. Pick a genre, mood and vocal and it writes the style line for you.
Open the Prompt Studio →