Tune your instrument by ear or by microphone: play a reference tone for guitar, violin, ukulele or bass, or let the live tuner listen and show the exact note plus how many cents sharp or flat you are. Free, private, no install.
What is an instrument tuner?
A tuner tells you whether a string or note is in tune. Pluck a string and the tuner shows the nearest note (for example E2 on a guitar) plus how far off you are in cents — 100 cents is one semitone. If it reads +12 cents you are slightly sharp and should loosen the string a touch; at −12 cents you are flat and should tighten it. When the readout hits 0 cents, the string is in tune.
Two ways to tune here
1. Reference tones. Pick your instrument and tap a string name to hear its exact pitch, then tune your string until it matches by ear. Guitar standard tuning is E2, A2, D3, G3, B3, E4. Violin is G3, D4, A4, E5. Ukulele (standard C tuning) is G4, C4, E4, A4. Bass is E1, A1, D2, G2.
2. Microphone tuning. Press the microphone button and allow access when your browser asks. Play one string at a time and the tuner shows the detected note, the frequency in Hz, and the cents deviation live. If your browser or page blocks microphone access, the tool says so plainly and the reference tones still work — nothing is faked.
Worked example: tuning a guitar’s low E
Choose guitar, press the microphone button, and pluck the thickest string. Suppose the readout shows D#2 at −35 cents: you are almost a semitone flat, so tighten the tuning peg slowly while plucking repeatedly until the display reads E2 and the cents drift toward 0. When it shows E2 within ±5 cents, that string is in tune — move on to A2 and repeat.
Tips for accurate tuning
Play in a quiet room, pluck one string at a time, and let the note ring rather than muting it. Tune up to the note where possible (if you overshoot, drop below and come back up) — this keeps string tension stable. New strings stretch: tune, play for a few minutes, and tune again.
Privacy
Microphone audio is analysed entirely in your browser and is never uploaded or recorded. Closing the page stops the microphone immediately.
Frequently asked questions
Why does the microphone button not work? Some browsers and embedded pages block microphone access. In that case the tool tells you and the reference tones still let you tune by ear.
What are cents? Hundredths of a semitone. 0 cents is perfectly in tune; ±5 cents is excellent for most players.
Can I tune other instruments? Any instrument whose notes fall in the tuner’s range works with the microphone mode, and the reference tones cover the four most common string instruments.
Is it really free? Yes — no account, no install, no catch.
How often should you tune?
Check tuning every time you pick the instrument up — temperature, humidity and plain playing pull strings out of tune surprisingly fast. Guitars left in a cold car or a warm room can drift a quarter-tone overnight. A thirty-second check before you play saves you from practising against a wrong pitch, which trains your ear badly over time. If you play daily, tune daily; if you play for an audience, tune right before you start and again after the first two songs, when new strings have settled.
Tuning in a noisy room
Microphone tuners listen to everything, so a television, another player or a barking dog can confuse the readout. If the note jumps around, move closer to the microphone, play one string at a time, and mute the other strings with your fretting hand. When the room is hopeless — a full band rehearsal, for example — the reference tones are the reliable fallback: plug in one earbud, match each string by ear, and you are set.
Related tools
Afinador de Instrumentos — versión en español · Online Metronome · Online Audio Visualizer.
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