Nearest note: A4, exactly in tune
Start quiet and raise the volume slowly, especially on headphones. A tone can damage hearing before it feels loud, and very low or very high frequencies sound quiet at levels that are not. This slider tops out at half of full scale, and audio only ever starts when you press Play.
The trace runs while a signal is playing.
- Frequency
- 440 Hz
- Note
- A4, exactly in tune
- Wavelength in air
- 0.78 m at 343 m/s
- Period
- 2.273 ms
- Hearing note
- Within the normal range of human hearing.
- Volume warning
- Start at a low volume, especially on headphones and at very low or very high frequencies: hearing damage can happen before a tone feels loud.
The WAV renders the same signal at half of full scale, about 6 dB of headroom, so it opens at a sensible level in any player no matter where the volume slider sits here. Everything runs in this tab: your files and inputs never leave your device.
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What it does
Generates sine, square, triangle, sawtooth, white noise, pink noise, and swept tones for testing speakers, subwoofers, headphones, and hearing. Type a frequency like 440 or 1kHz, or a note name like A4 or C#3, and the page describes the resulting signal: exact frequency, nearest note, wavelength in air, period, and where it falls relative to human hearing.
How to use it
Type a frequency or note into the input, pick a waveform, and adjust duration, volume, and (for a sweep) the end frequency and sweep shape. The panel plays the tone on demand through your speakers or headphones and can export the same signal as a WAV file. Nothing plays automatically.
Why this one
Most online tone generators run flash-era interfaces, autoplay audio the moment the page loads, or gate the sweep and noise modes behind a paywall. This one starts silent, exposes the exact math behind the sweep, and works fully offline once loaded, with no ads and no account.
FAQ
- Is it safe to play these tones at full volume?
- No. Start at a low volume, especially on headphones and at very low or very high frequencies, since a tone can cause hearing damage before it feels loud. Raise the volume slowly and stop if anything feels uncomfortable.
- Why can I not hear an 18 kHz tone that the page says it is playing?
- Human hearing typically tops out well below 20 kHz, and that ceiling drops with age, most noticeably above about 15 to 17 kHz. The tone is genuinely being generated even if your ears, headphones, or speakers cannot reproduce it.
- How do I use a sweep to test a subwoofer?
- Pick the sweep waveform, set the start frequency low (try 20 Hz) and the end frequency around 200 Hz with a logarithmic shape, then play it at a moderate volume and listen for rattles, buzzing, or a sudden drop in output, which usually mark the edge of the subwoofer's range or a loose panel.
Keyboard shortcuts: press ? anywhere on this page to see them.