Online Instrument Tuner (Guitar, Bass & Ukulele)
A tuner that listens to your microphone, finds the pitch and shows the note and how many cents sharp or flat it is on a meter. Choose a preset for guitar, bass or ukulele strings, or use chromatic mode to check any note. To keep time while you practise, try the Metronome. Audio is analysed on this page only; nothing is recorded or sent anywhere.
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Press "Start microphone", then play the string you want to tune, one at a time.
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Listening for a note…
-500+50
-cents|Detected frequency: -
Strings
The string closest to the note you play is picked automatically.
How to use
- Choose the "Instrument / tuning". If you are not sure which note you are on, choose "Chromatic".
- Press "Start microphone" and allow microphone access in your browser.
- Pluck one open string at a time. The note name and the meter appear.
- Turn the tuning peg until the meter sits in the centre (within ±5 cents). Tighten if it says "Flat", loosen if it says "Sharp".
Notes
- Microphone permission is required. Nothing is recorded; the sound is only used to work out the pitch on this page.
- Background noise and the ringing of other strings can throw off detection. Use a quiet place and play one string at a time.
- The pitch is worked out from browser audio, so it can be less accurate than a dedicated clip-on tuner. Low notes, such as the low strings of a bass, are the least steady.
- Built-in or cheap microphones can miss quiet or low notes. If you play through an amp or speaker, watch out for feedback.
- With an electric guitar or bass, point the microphone at the amp or speaker. If you use an audio interface, pick it as the input device.
- The reference pitch (A4) is normally 440 Hz. If you play with others, match their reference.
Glossary
Pitch
How high or low a sound is, measured as its frequency in Hz (vibrations per second). The A above middle C (A4) is normally 440 Hz, and each octave up doubles the frequency.
Cent
A unit for small differences in pitch: a semitone is 100 cents. Most people cannot hear an error within ±5 cents.
Reference pitch (A4)
The frequency assigned to A4, which everything else is tuned from. It is usually 440 Hz, though some orchestras use 442 Hz.
Open string
A string played without pressing it against a fret. Tuning is done by matching the open strings.
Drop D
A guitar tuning where the lowest (6th) string is lowered a whole step to D, with the other strings unchanged from standard.
FAQ
Is my microphone audio recorded or sent anywhere?
No. The audio is only used on this page to work out the pitch. It is never recorded, stored or uploaded. The microphone is released when you press Stop or leave the page.
No note is detected, or the meter keeps jumping around.
Use a quiet room and play one string at a time. Other strings ringing, or a note that is too quiet, prevent detection. Low notes such as a bass low string are the least steady, so pluck firmly and let the note sustain.
It sometimes shows a note an octave higher or lower than expected.
Guitar strings often have overtones stronger than the fundamental, which can be picked up by mistake. This tuner favours the fundamental, but the moment right after plucking is unstable, so read the meter a little after the attack.
How do I tune an electric guitar or bass?
Point the microphone at the amp or speaker. If you use an audio interface or a line input, select it as the input device in your browser and you can tune from it directly.
What should I set the reference pitch (A4) to?
Normally 440 Hz. If you play with a piano or other players and sound out of tune together, match their reference (for example 442 Hz); it can be set between 410 and 480 Hz.
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