440 Hz tone
Concert A, the tuning standard.
Volume first. Turn your device volume down before pressing play, then raise it slowly. Tones start quiet on purpose. Keep headphones off your ears until you know how loud it is.
Hz
Logarithmic slider, 1 Hz to 22 kHz. Space bar starts and stops.Waveform
0 dBFS is the loudest your device can play; every 20 dB lower is a tenth of the amplitude.
What 440 Hz is used for
ISO 16 sets A4 at 440 Hz as the standard tuning pitch. Orchestras tune to it (often from an oboe) and so do most electronic tuners.
| Period | 2.273 ms |
|---|---|
| Wavelength in air (20 °C) | 78.0 cm |
| One octave down / up | 220 Hz / 880 Hz |
The generator above starts at 440 Hz. You can still move the slider to any other frequency, or open the full tone generator.
Questions people ask
Why can't I hear the 440 Hz tone?
Check the tab is not muted and the correct output device is selected. 440 Hz is well within the range of nearly every speaker and headphone.
How long is one cycle of 440 Hz?
2.273 milliseconds. In room-temperature air the wavelength is about 78.0 centimetres.
Keep testing
- Tone generatorSine, square, triangle and sawtooth from 1 Hz to 22 kHz.
- Frequency sweepLogarithmic or linear sweeps over any range and duration.
- Speaker testChannel, range and polarity checks for stereo speakers.