Online Tuner
Chromatic tuner that listens through your microphone — no app, no upload.
A chromatic tuner that works with any instrument — guitar, bass, violin, ukulele, flute, voice. It listens through your device microphone and detects the pitch on the device itself using autocorrelation, the same technique most tuner apps use.
Your microphone audio is analysed on this device only. Nothing is recorded or sent anywhere.
How to use
- Press Start tuning and allow microphone access — the browser asks once per site.
- Play one note at a time, close to the microphone. The big letter is the nearest note; the needle shows how far off you are.
- Needle centred (within about ±6 cents, shown green) means in tune. Left is flat — tighten; right is sharp — loosen.
- For guitar, tap a string button first to see its exact target frequency.
About this tool
No recording is made and no audio leaves your device; the microphone stream is analysed sample-by-sample in this page and discarded. Reference pitch is A4 = 440 Hz.
Phone microphones struggle below about 40 Hz and room noise can confuse any tuner — a quiet room and one note at a time give the steadiest reading.
How it works
The tuner estimates pitch with autocorrelation: it compares the microphone waveform with delayed copies of itself and finds the delay where the signal matches best — that delay is the period of the note, and frequency is 1 ÷ period. A short refinement (parabolic interpolation around the best match) sharpens the reading to a fraction of a hertz.
Notes are measured against the equal-temperament grid anchored at A4 = 440 Hz. The distance from the nearest grid note is shown in cents, one cent being 1/100 of a semitone: cents = 1200 × log₂(your frequency ÷ the note’s exact frequency). ±6 cents is a practical “in tune” window; ±50 cents means you are halfway to the neighbouring note.
Worked examples
New guitar strings: New strings stretch and drift flat for days. Tune each string to its target (E2 82.4 Hz up to E4 329.6 Hz), play for ten minutes, then run the tuner again — chasing the needle once a day gets boring fast, and the tuner makes each pass a one-minute job.
Violin practice intonation: Play a slow scale against the tuner open on the table. Beginners are usually surprised by the major third: the needle shows what “sounds right” hides — most people play it 10–15 cents sharp until they train against a reference.
Quick reference
| Instrument | Standard tuning (low → high) |
|---|---|
| Guitar | E2 · A2 · D3 · G3 · B3 · E4 |
| Bass guitar | E1 · A1 · D2 · G2 |
| Ukulele | G4 · C4 · E4 · A4 |
| Violin | G3 · D4 · A4 · E5 |
| Viola | C3 · G3 · D4 · A4 |
| Cello | C2 · G2 · D3 · A3 |
| Mandolin | G3 · D4 · A4 · E5 |
Frequently asked questions
How accurate is it?
In a quiet room the detection typically lands within a few cents of the true pitch — the same order as dedicated tuner apps. Very low bass notes and noisy rooms reduce accuracy because a phone microphone hears less of the fundamental and more of the room.
Which instruments does it work with?
Anything that plays one sustained note at a time: guitar, bass, violin, viola, cello, ukulele, mandolin, flute, clarinet, trumpet and voice. Chords will confuse it — tune one string or note at a time.
Is my audio recorded or uploaded?
No. The microphone stream is processed in your browser to measure pitch and is never stored or transmitted. Closing the tab ends access; the Stop button ends it immediately.
The needle jumps around. How do I get a steady reading?
Move closer to the microphone, mute other sound sources, and play a clean single note at moderate volume. Pizzicato strings decay fast — bow or re-play the note to keep the reading alive.
What does “cents” mean?
A cent is 1/100 of a semitone. Being 50 cents off means halfway to the next note — very out of tune. Within ±6 cents even trained ears hear the note as in tune in most contexts.
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