How to use the 440 Hz tone
- Press Play to hear a pure sine wave at 440 Hz, the note A above middle C.
- Tune your instrument's A string or note until it matches without "beating" (a slow wobble means you are close but not exact).
- Use the semitone buttons to move to other notes, or download a WAV file to play on another device.
Why 440 Hz?
A4 = 440 Hz is the international standard concert pitch, adopted by the International Organization for Standardization as ISO 16 and used by most orchestras, bands, keyboards and tuners. Before standardisation, pitch varied widely between cities and eras; some orchestras today tune slightly higher, to 442 or 443 Hz, for a brighter sound. You may read claims online that 432 Hz is more "natural" or healing; there is no scientific evidence for that, but you can type any frequency to compare.
When tuning by ear, listen for beats: two tones a few hertz apart produce a regular pulsing whose speed equals the difference in frequency. As you approach 440 Hz, the beating slows and disappears. The tone is generated live in your browser.
FAQ
What note is 440 Hz?
A4, the A above middle C.
Should I tune to 440 or 442 Hz?
Use 440 unless your ensemble specifies otherwise; many European orchestras use 442–443.
Can I download the tone?
Yes. Choose a length and press Download WAV.