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Tone Generator

Play a pure tone at any frequency: to tune an instrument, test speakers and headphones, find a rattle, or check which high tones you can hear.

Runs in your browser · No uploads

440 Hz

A4

The slider covers 20 Hz to 20,000 Hz with equal room for each octave. Type a frequency below for 1 Hz to 22,000 Hz.

A letter, an optional ♯ (#) or ♭ (b), and an octave: middle C is C4.

Waveform
Speakers

Start quietly. High volumes and very high or very low tones can damage hearing and speakers, and some people can't hear tones above about 15,000 Hz at all.

Sweep
Sweep
Save as a sound file

A 16-bit, 44.1 kHz WAV file made on your device, with the frequency, waveform, speakers and volume chosen above.

Keyboard: Space plays and stops, ← and → change the frequency by a semitone (with Shift by an octave).

  • Nothing leaves your device
  • No server-imposed size limits
  • No sign-up, no watermark
  • Free

How to play a tone

  1. Turn your volume down first.
  2. Set the frequency with the slider or type it in hertz, or type a note such as A4 or C#5.
  3. Choose a waveform and which speakers to play it on, then press Play (or the space bar).
  4. Use the semitone and octave buttons, or ← and →, to move between notes.

Waveforms

  • Sine: a single pure frequency, the usual test tone.
  • Square and sawtooth: buzzy tones with many overtones, easier to hear on small speakers.
  • Triangle: softer than square, with weaker overtones.

Sweeps and speaker tests

A sweep glides from one frequency to another, which shows where speakers lose bass or treble and makes rattles easy to find. "Even per octave" spends the same time on each octave, the way we hear pitch; "even per hertz" moves at a constant number of hertz per second.

Left only and Right only play the tone on one side, to check that headphones and speakers are wired the right way round.

Notes and tuning

The note closest to the frequency is shown with how many cents (hundredths of a semitone) it is above or below. Notes are tuned to A4 = 440 Hz; change this for orchestras tuned to 442 Hz or for baroque pitch (415 Hz).

Saving a tone

Download WAV writes the steady tone or the sweep as a 16-bit, 44.1 kHz WAV file, made on your device. It plays in any audio player and opens in any audio editor.

Frequently asked questions

Is this a hearing test?

No. It can show roughly which high tones you hear on your own equipment, but headphones, speakers and volume all change the result. See a hearing professional for a real test.

Why can't I hear very low or very high tones?

Small speakers can't play deep bass, and most adults can't hear above about 15,000 to 17,000 Hz. Don't turn the volume up to find out: you may suddenly hear it far too loud.