🎛️ Online Tone Generator

Want to test your hearing? Try a simple tone generator right inside your browser. Pick any frequency between 20 Hz and 20 kHz, and it plays straight through. No app downloads. No account signup. Just pick your waveform, dial in the exact hertz you want, and watch the musical note pop up in real time so you know what you're listening to.

You can send the tone to one ear or both — whichever works for you. Need to check your hearing range? Run a slow sweep across the full spectrum and listen as it climbs from low to high. The sound gets generated on your device, stays on your device, and never gets recorded anywhere. Super straightforward.

440Hz
Nearest note: A4
in tune (0 cents)
Frequency Hz
A4 =
Waveform
Output channel
Volume35%
Quick presets
Set your volume low first, then press Play. Sound is generated locally — nothing is recorded.

Space play / stop  ·  nudge 1 Hz  ·  Shift + nudge 10 Hz. Your last settings are remembered on this device.

🔬 Hearing-range sweep

Glides slowly from 20 Hz up to 20 kHz so you can hear where your ears roll off at the top. Turn the volume down before you start — the mid‑high frequencies get piercing. Note the number on the display at the moment the tone fades to silence: for most adults that's somewhere between 14 and 17 kHz, and it drops with age.

Idle.

How to use the tone generator

1
Turn your system volume down first.

A pure tone is louder and more fatiguing than music at the same setting. Start with the on‑screen Volume slider around 20–30%, press Play, then raise it only if you need to.

2
Set the frequency.

Drag the slider for a quick sweep by ear, type an exact value like 440 or 261.63 into the Hz box, tap a preset, or use the −1 Hz / +1 Hz and octave buttons for fine control. The big readout shows the nearest musical note and how many cents sharp or flat you are.

3
Choose a waveform.

Sine is a single pure frequency — use it for tuning, hearing checks and reference tones. Square, triangle and sawtooth add harmonics and sound brighter or buzzier, which is handy for testing speakers, filters and sound design.

4
Send it left, right or both.

Use the Output channel buttons to check a single speaker or one side of a pair of headphones. Pair this with the Speaker Test if you're chasing a dead channel.

What people use a tone generator for

Tuning instruments

Play a reference pitch — 440 Hz for concert A, 261.63 Hz for middle C, or switch the A4 reference to 432 or 442 Hz — and match your string, reed or drum head to it by ear. The cents readout tells you which way to adjust.

Testing speakers and subwoofers

Sweep low frequencies to find where a speaker stops producing usable bass, listen for buzzes and rattles in a cabinet or a room, or check that a subwoofer crossover is doing its job. A steady 1 kHz sine is the classic level‑setting and channel‑balance tone.

Checking your hearing range

Use the sweep, or step through the 8 kHz / 15 kHz presets, to get a rough idea of your high‑frequency limit. It's not a medical test, but a noticeable difference between your two ears, or a limit well below 14 kHz for a younger person, is worth mentioning to an audiologist.

Audio equipment and cable checks

Feed a known tone into an interface, mixer or amp and confirm it comes out clean at the same frequency. Tones make hums, ground loops, distortion and intermittent connections much easier to hear than music does.

Sound design and learning

Hear the difference between sine, square, triangle and sawtooth at the same pitch, get a feel for how octaves double the frequency, or generate a drone to layer under something else.

Frequently asked questions

Is this tone generator really free?

Yes — no account, no download, no time limit. The tone is synthesised in your browser with the Web Audio API, so there's nothing to pay for and nothing to install.

What frequencies can it play?

Anything from 20 Hz to 20,000 Hz, which covers the full range of typical human hearing. Use the slider for a broad move, or type an exact figure such as 432 or 261.63 for precise work.

Is my microphone or audio being recorded?

No. This page only plays sound. It never requests microphone access, and nothing about your session is stored or sent anywhere. Your last slider and waveform settings are saved only in your own browser, so the tool opens the way you left it.

I can't hear the low tones — is something broken?

Probably not. Laptop and phone speakers physically can't reproduce much below roughly 150 Hz, so tones in the 20–80 Hz range need good headphones or a subwoofer. If a mid‑range tone like 1 kHz plays fine, the tool is working.

Why does the tone sound like it has a slight "beat" or wobble?

If you're playing sound from two speakers in a room, reflections combine and cancel at different points, which can make a steady tone seem to pulse as you move your head. On headphones a single tone should sound perfectly smooth.

Can I use it as a hearing test?

Only as a rough, informal check. A real audiogram is done in a sound‑treated room with calibrated equipment. This is useful for comparing your two ears or getting a ballpark high‑frequency limit, not for diagnosis.

What's the safest way to use it?

Lower your volume before pressing Play, especially before a sweep or a high‑frequency preset. Pure tones can mask the fact that they're loud until they're already uncomfortable. If you have tinnitus, be cautious with sustained tones and stop if anything feels irritating.

This tone generator plays audio only — it never accesses your microphone, and nothing you hear is recorded or uploaded. It is not a calibrated instrument and is not a substitute for a professional hearing test.