🎵Tone generator

✓ Tested & verified Updated: Aug 11, 2026 How the test works

Tone generator

Every tone fades in from silence and fades out again, so nothing ever clicks. −20 dBFS is the loudest this page will ever play — anything above that is your own volume control.

Tone playing

440Hz

Set a frequency and press play. The nearest musical note and the deviation in cents are worked out from the frequency, so this doubles as a tuning reference — A4 is 440 Hz by definition.

Nearest note—
Off by—
Wavelength in air—
Now playingsilent

Frequency

Wave shape

Send it to

Output level

Try also

How do I play one exact frequency?

The tone generator plays a single sine wave at the frequency you set and reports two numbers: the frequency in Hz and the output level in dBFS. The level is the part other generators leave out, and it is what makes a tone repeatable — the same 1 kHz at −20 dBFS today and next week, rather than whatever the slider happened to be near.

A pure tone is a diagnostic instrument. One frequency at a time removes music, codecs and content from the picture, so a buzz that only appears at 120 Hz is a mechanical resonance, and a tone that vanishes above 14 kHz is the top of either your speakers or your ears.

Nothing is downloaded: the wave is built in the browser, so the frequency is as accurate as your audio clock and no network condition can colour it. Start quietly, especially high and low, where levels are deceptive.

If you are hunting a specific problem rather than exploring, these are the frequencies worth typing first, and what each one is good for.

Frequency	What lives there	What it is useful for
20–60 Hz	Sub-bass; felt more than heard	Finding whether a subwoofer is doing anything at all
60–150 Hz	Bass fundamentals, and most cabinet resonance	Making a desk, a panel or a loose screw give itself away
150–400 Hz	The body of a voice	Judging boxiness in a laptop or a conference speaker
440 Hz	Concert A, the reference musicians tune to	Comparing two devices by ear on neutral ground
1 kHz	The standard reference tone in audio engineering	Setting levels; a dead 1 kHz channel is a genuine fault
2–4 kHz	Consonants, and the peak of human sensitivity	Checking clarity, and hearing harshness for what it is
8–12 kHz	Air and cymbals	Comparing the two channels of a pair against each other
15–18 kHz	The region that fades first with age	Curiosity, with the caveat that speakers fade here too

Fixed test tones already exist elsewhere on this site, and they answer different questions. The speaker test plays seven set frequencies one channel at a time because its subject is routing, not pitch, and the headphone test adds polarity. This page hands you the dial instead. To sweep the whole range in one pass rather than stepping through it, use the frequency test; to push downward until the tone disappears, the bass test does that with the level held steady, and the hearing test does the same at the top of the range. If what you actually need is the format your machine is sending, that is the audio test.

Frequently asked questions

What are 432 Hz and 528 Hz tones supposed to do?

They are ordinary frequencies with an unusual following. 432 Hz is an alternative concert pitch, a little under the standard 440 Hz, and 528 Hz appears in claims about healing and repair; neither claim has support in published research, and no reputable measurement has separated their effects from expectation. The generator will play both exactly, and it treats them like every other number you type — as a frequency, not a remedy.

How do I play the high-pitched tone teenagers can hear?

Set the frequency between 17 000 and 18 000 Hz and raise the level slowly. Whether anyone hears it depends on two things at once: sensitivity above 15 kHz that most people lose gradually with age, and the speakers, because small drivers and Bluetooth voice profiles roll off before the tone ever reaches the room. A phone speaker failing at 17 kHz proves nothing about the listener, which is why this page shows the level it is sending rather than declaring a verdict.

Is a sine wave generator the same thing?

Yes, and the shape is what makes it useful. A sine wave holds all of its energy at one frequency, so anything else you hear was added by the speaker, the cabinet or the desk. Square and sawtooth waves carry a stack of harmonics on top of the fundamental, which sounds louder and harsher and makes it impossible to say which frequency caused what — the reason test tones are sine waves nearly everywhere.

Why does the same level sound much quieter at 100 Hz than at 1 kHz?

Because human hearing is not flat and no speaker is either. Sensitivity peaks in the 2 to 4 kHz region, where speech consonants live, and falls away steeply toward the bottom of the range, so a tone at an identical digital level can sound half as loud at 100 Hz and painfully bright at 3 kHz. Small drivers exaggerate it further by producing almost nothing below 150 Hz. Judge tones against the same tone on another device, never against the tone next to it.

Can a test tone damage speakers or hearing?

Both are possible with sustained tones at high level, which is why the level is on screen. A continuous low-frequency tone pushes a driver far harder than music does, and tweeters are the usual casualty of loud sustained high tones; for ears, it is duration at volume rather than the frequency that does harm. Start low, raise gradually, and never turn the system volume up while a tone is already playing — you cannot judge a frequency you cannot yet hear.

How the test works

The tone is one oscillator node set to a sine wave, connected to a gain node and then to the output — the shortest possible chain, so nothing between the maths and the speaker can colour it. Frequency accuracy comes from the audio clock rather than from the page, which is why a value is played as the exact number you typed rather than the nearest step on a slider. The level is applied as linear gain and displayed in dBFS with 20 × log10(gain), the same scale the mic test reads: 0 dBFS is full scale, −6 dBFS is half of it, and −20 dBFS is a tenth. Every start and stop is ramped over a few milliseconds because an abrupt edge in a waveform is a click, and a click contains the whole frequency range at once. The page controls only what it sends. What reaches your ears is shaped by the output device, the amplifier and the room, so this is an instrument rather than a verdict, and nothing is recorded or uploaded.

Worked example

With frequency 440 Hz, level −20 dBFS, this page works out A4, exactly on pitch. This is where voices and most instruments live, so it is the range every speaker gets right and no speaker can hide. Nothing is playing yet.

NoteA4
Wavelength in air78 cm (30.7 in)
Amplitude at −20 dBFS0.10 of full scale

Sources:

Why the level is on screen

A tone without a level is not a measurement. Two people comparing results need the same frequency and the same amplitude, and only one of those is usually written down.

dBFS is the honest unit here. It describes what the page sends, from 0 dBFS at the digital ceiling downward. What arrives at your ear depends on the amplifier, the drivers and the volume control, so no web page can claim decibels of loudness in the room.

Fades are not decoration. A sine wave that starts or stops instantly produces a click containing every frequency at once, which is exactly what a single-frequency test is trying to avoid.