Tone generator
Emit a pure tone: sine/square/triangle, 20 Hz to 20 kHz.
- Instant
- Free
- Private (processed locally)
- No sign-up
A pure tone, on demand
Testing a speaker, checking your hearing, creating a reference note: this generator emits an exact frequency from 20 Hz to 20 kHz, in the waveform you want, and shows the nearest note.
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Set the frequency
With the slider or keyboard, 20 to 20,000 Hz.
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Choose the wave
Sine for a clean test, or square/triangle/sawtooth.
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Play
Adjust the volume before starting the sound.
A few landmarks
| Frequency | Landmark |
|---|---|
| 20 Hz | Low limit of hearing |
| 440 Hz | Reference A (note A4) |
| 1,000 Hz | Common test tone |
| 20,000 Hz | High limit of hearing |
Lower the volume before starting, especially in the highs. Sound needs a click to start (browser policy).
Frequently asked questions
What is a tone generator for?
To produce a pure sound at an exact frequency: test speakers or headphones, spot a room resonance, check the range of your hearing, create a reference note for tuning, or generate a calibration signal.
Which waveforms and why?
The sine is the purest sound (a single frequency). Square, triangle and sawtooth add harmonics and sound “richer” or more “aggressive”. The sine is recommended for hearing tests.
Which note matches a frequency?
The tool shows the nearest note: 440 Hz is A4, the orchestral reference. Each doubling of frequency goes up one octave: 880 Hz is A5, 220 Hz is A3.
Are very high frequencies audible?
The human ear hears about 20 Hz to 20 kHz, but the high limit drops with age: many adults no longer hear beyond 15-16 kHz. Lower the volume before testing the extremes.