How to read your result
The big letter is the note, with its octave number: C4 is middle C and A4 is the note orchestras tune to. A ♯ (sharp) is a black piano key, for example C♯4 sits between C4 and D4.
The frequency is the pitch in hertz (Hz), shown to one decimal place. With the usual reference of A4 = 440 Hz, middle C is 261.63 Hz.
The gauge shows how far you are from the note in cents. 100 cents is one semitone, so the gauge covers half a semitone each way, from −50 to +50.
| Gauge | Meaning | What to do |
|---|---|---|
| In tune | Within 5 cents of the note (the green band) | Nothing to change. |
| Sharp | More than 5 cents above the note, needle right of centre | Lower the pitch: loosen the string or relax your voice. |
| Flat | More than 5 cents below the note, needle left of centre | Raise the pitch: tighten the string or lift your voice. |
The detector listens for one clear, steady note between about 40 Hz and 4,200 Hz, from a low bass string to the top of a piano. To keep the reading calm, it ignores sounds that are not clear enough (clarity below 0.9 out of 1) or quieter than −50 dB. Talking, chords, breath and background noise usually fall below that line.
When the sound stops, the last note stays on screen for 1 second in a lighter colour.
The pitch line under the gauge shows the last 8 seconds. Each horizontal line is one semitone, so you can see whether a held note stays steady or drifts.
Reference A4 is the pitch everything else is measured from. It starts at 440 Hz and can be set from 415 to 466 Hz. Change it if your band, choir or orchestra tunes to a different A. Your choice is saved in this browser.
Troubleshooting
The browser didn’t ask for permission, or I clicked Block
Your browser remembers the choice for this site. Click the icon to the left of the address bar, allow the microphone, then reload the page. The test panel shows the exact steps for your browser if access is blocked.
“We can’t hear a clear note yet”
- Sing a steady vowel such as “ah”, or play one note and let it ring.
- Move closer to the microphone, or raise the input volume in your system sound settings.
- Check that the right microphone is selected in the panel.
The note jumps around or shows the wrong octave
Some instruments produce strong overtones, which can read as the note an octave up. Play one string at a time, mute the others, and pluck gently. A clean, held note gives the steadiest reading.
Low bass notes don’t show
Phone and laptop microphones pick up deep bass weakly. Hold the microphone close to the instrument or amplifier, or tune using the harmonic at the 12th fret, which is one octave higher.
“Your microphone is busy”
Another app is holding the microphone. Close video call apps, recording software or other browser tabs that use it, then try again.
Windows, Mac, iPhone and Android privacy settings
Operating systems can block the microphone for every browser at once.
- Windows: Settings, then Privacy and security, then Microphone. Turn on Microphone access and Let desktop apps access your microphone.
- macOS: System Settings, then Privacy and Security, then Microphone. Turn on your browser, then quit and reopen it.
- iPhone and iPad: Settings, then Apps, then your browser, then turn on Microphone.
- Android: Settings, then Apps, then your browser, then Permissions, then Microphone.
Privacy
Sound from your microphone is analysed on your device to find the pitch, and it is never recorded, stored or sent anywhere. Only your A4 setting is saved, in this browser. How it works