Online tone generator
Pick a frequency with the slider, the number box or a quick button, choose the wave and press Play. The note name and cents show for every frequency.
- 1 Hz to 22 kHz
- Free, no sign-up
Hz
A4
Frequency sweep
Start quietly and raise the volume slowly, especially with headphones and above 10 kHz.
Runs in your browser. Nothing you type or open is uploaded. Free to use, no account. More audio tools
How to use it
- Set the frequency: drag the slider, type a number or press a quick frequency.
- Choose the wave, the volume and which speaker plays it.
- Press Play, and use the step and octave buttons to move in small or big jumps.
Ways to use a test tone
Musicians tune to A4 at 440 Hz or C4 at 261.63 Hz. Audio setups use 50 or 60 Hz to find mains hum, low tones to check a subwoofer, and 1 kHz as a reference level. The sweep glides from one frequency to another over the time you set, logarithmically so each octave gets the same time, which makes rattles and dead spots in a speaker easy to hear.
High tones help you check your hearing range: most adults hear up to about 15 to 17 kHz, and the limit drops with age. The left and right options check stereo wiring. Square and sawtooth waves carry many harmonics, so they sound louder and brighter than a sine wave at the same setting.
Private by design
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Questions
How do I play a 440 Hz tone?
Press the A4 440 Hz button, then Play. The slider, the number box and the note name all update together.
Can I play a tone in only one ear?
Yes. Set Play through to Left only or Right only. This is a quick way to check headphone and speaker wiring.
Why can I not hear the highest frequencies?
Hearing above 15 kHz fades with age, and many phone and laptop speakers roll off high notes too. Try headphones, and raise the volume slowly.
Is a tone generator safe for my speakers and ears?
Start at a low volume, especially with headphones and very high or very low tones, and raise it gradually. Long, loud tones can tire your ears and stress small speakers.
What is the sweep for?
A sweep moves smoothly between two frequencies. Listening for buzzes, rattles or quiet spots during a sweep is a quick speaker and room check.
From the same developer
- Mic to Speaker: the matching app.
