Tuner and metronome
Play a note into the microphone and read the note name, the octave and how far off it is in cents. The A4 reference is adjustable from 415 to 466 Hz, and the metronome runs without the microphone. Both work entirely inside the browser.
Tuner
Waiting for a note
- Off by (cents)
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- Heard
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- Target
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- Note
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440 Hz by default. Orchestras often use 442, early-music groups 415 — match whoever you are playing with.
Metronome
ModeratoBeats per minute, from 30 to 300.
The downbeat is higher and louder. Turn it off and every beat sounds the same.
If you do not know the tempo, tap this button along with the music four or five times and the BPM fills in.
To find the key or tempo of a recording, use the key & tempo changer (/audio/pitch-tempo)
Related tools
All tools- Audio cut & joinCut the part you need out of an audio file, or join several into one.
- Silence removerFind the silent stretches in a recording and close them up.
- Volume & level matchRaise or lower audio by dB, or match peak or loudness across several files.
- Voice recorderRecord from your microphone, play it back, save as WAV or MP3.
Highlights
- Measured as a period, not as a spectrum
- Reading the peak of an FFT gets coarser the lower the note goes: an 8192-point transform at 44.1 kHz has 5.4 Hz bins, which at A2 (110 Hz) is about 85 cents — far too blunt to say whether a string is in tune. This measures the repetition period of the waveform directly and interpolates it, which resolves well under a cent even in the bass.
- Octave errors are held down
- A harmonically rich note correlates just as strongly at twice its period, so taking the strongest match reports a guitar’s low E an octave up. The McLeod rule — the first peak that clears 90% of the best one — is used instead, and the displayed figure is the median of the last five readings, so the needle does not jump an octave mid-note.
- Nothing is recorded or uploaded
- Microphone audio is used only to count frequency inside the page. It is never stored and never sent anywhere, and stopping the microphone ends the capture immediately. The metronome needs no permission at all.
How to use it
Allow the microphone
Press "Use the microphone" and the browser will ask for permission; choose Allow and the input starts. If it was refused, or the page is not on an https address, the reason and the fix appear on screen.
Play a note and read the needle
Play a single note and the note name, its target frequency and the deviation in cents appear. When the needle sits inside the centre band the readout says it is in tune. Change the A4 reference field, anywhere from 415 to 466 Hz, to match whoever you are playing with.
Run the metronome
Set the tempo and the beats per bar, then press Start. If you do not know the tempo, tap the tap-tempo button along with the music a few times. The downbeat accent and the volume are switchable, and none of it needs the microphone.
Reading the display
- What is a cent?
- One hundredth of a semitone — about 0.06% in frequency. Listening to two notes in succession, most people start to hear a difference somewhere around five cents, which is why anything inside ±5 counts as in tune here. A note being played moves by a few cents anyway as finger pressure and breath change, so a perfectly still needle is not the goal.
- Which A4 reference should I use?
- 440 Hz is the modern standard and the default. Orchestras often sit at 442 or 443 for brightness, and baroque ensembles commonly use 415, a semitone down. In an ensemble the value only helps if everyone uses the same one, so match the group. If there is a piano in the room, match the piano — it is the instrument that cannot be moved.
- Why does the needle wander?
- Pitch moves during the first few tens of milliseconds of any note, and then keeps moving with vibrato and breath. Room noise and another instrument nearby will move it too. Read the sustained part of the note rather than the attack; if it still refuses to settle, move closer to the microphone or quieten the room.
- Which way do I turn the peg?
- More tension is a higher note, so "sharp — loosen" means back the peg off and "flat — tighten" means take it up. Approaching the target from below takes up the slack in the machine head and holds better. On a wind instrument, pulling the tuning slide out lowers the pitch and pushing it in raises it.
Questions
- Which instruments does it work with?
- Anything monophonic: guitar, bass, ukulele, violin, wind instruments and the voice. The detection range runs from roughly 27.5 Hz (A0) to 1400 Hz, which covers nearly the whole piano and the bottom of a bass guitar. Chords and two instruments at once cannot be measured — play one note at a time.
- I refused the microphone prompt by mistake.
- Open the padlock or camera icon at the left of the address bar, set this site’s microphone to Allow, and reload the page. On a phone the same setting lives in the browser’s site settings. Note that microphone access is only offered on encrypted (https) connections.
- Is the audio recorded?
- No. Samples from the microphone are used to count frequency and then discarded. Nothing is written to disk and nothing is sent to a server. Pressing "Stop the microphone" or closing the page ends the capture.
- The metronome tempo feels slightly uneven.
- The clicks are booked ahead on the audio clock, so the tempo itself does not drift no matter how busy the page is. The on-screen lamps do follow the display refresh, so in a background tab the lamps can appear to freeze while the sound carries on unaffected.
- Will the tuner hear the metronome?
- Not through headphones. Through speakers it can: the click is a clean tone and the tuner will happily measure it. Stop the metronome or turn it down while you tune.