Online Instrument Tuner
Tune your bass, guitar, or ukulele using your microphone. Pick an instrument and tuning, play a string, and follow the needle.
What is this?
A free chromatic tuner that runs entirely in your browser. It listens through your microphone, detects the pitch of the string you play, and tells you whether to tighten or loosen it. It supports 4- and 5-string bass, electric and acoustic guitar, and ukulele — each with its most common alternate tunings.
How it works
Pick your instrument and tuning, then enable the microphone. Audio is processed locally — nothing is recorded or sent anywhere.
Play one open string at a time. The tuner detects which string you're playing automatically, or tap a note pin to lock onto one string.
Watch the needle. Left of center means too low (tighten); right means too high (loosen). Green means you're within 5 cents — in tune.
Standard tunings
Each dot marks a note in that instrument's standard tuning. Brighter columns are shared by more instruments — the tuner above covers guitar, bass, and ukulele in detail; this table also covers banjo, mandolin, and the violin family.
| G 9/9 | D 8/9 | A 8/9 | E 6/9 | C 3/9 | B 2/9 | |
|---|---|---|---|---|---|---|
| Guitar | ||||||
| Bass guitar | ||||||
| Ukulele | ||||||
| Banjo | ||||||
| Mandolin | ||||||
| Violin | ||||||
| Viola | ||||||
| Cello | ||||||
| Double bass |
G, D and A are the most universal — they appear in guitar, bass, mandolin, and the entire violin family (violin, viola, cello). Standard tuning only; drop, open, and alternate tunings vary.
Frequently asked questions
Why isn't the tuner picking up my instrument?
Make sure your browser has microphone permission and you're in a reasonably quiet room. Play one string at a time, close to the microphone, and let it ring. Very low bass strings carry less energy through laptop mics — plucking firmly over the pickup area helps.
What does "cents" mean?
A cent is 1/100 of a semitone. The meter shows how far your string is from the target pitch, from −50 (a quarter tone flat) to +50 (a quarter tone sharp). Within ±5 cents is considered in tune for practical purposes.
Which tuning should I use?
If you're not sure, use Standard. Drop tunings (Drop D, Drop C) lower only the thickest string for heavier riffs; Half Step and Full Step Down shift every string equally and are common in rock. BEAD gives a 4-string bass the range of a 5-string's lowest four strings.
Why does the needle drift as the note fades out?
As a string's sound decays, its overtones can briefly become louder than the fundamental pitch, which nudges the reading. Trust the needle in the first couple of seconds after plucking, and pluck again for a fresh reading.
Is my audio recorded or uploaded?
No. Pitch detection runs entirely on your device using the Web Audio API. No sound ever leaves your browser.
Should I tune up or down to the note?
Always tune up. If a string is sharp, loosen it below the target and come back up to pitch — strings hold tune better when the final motion tightens them.
What is the reference tone button for?
It plays the exact target pitch of the selected string so you can tune by ear — useful in noisy rooms, or if your microphone isn't available. Match your string to the tone until the "beating" between the two sounds disappears.
Why do new strings keep going out of tune?
Fresh strings stretch during their first hours of playing. Tune, gently pull each string away from the fretboard, and tune again — repeat a few times and they'll settle. Temperature changes also detune any instrument, so retune after moving rooms.
Does it work with an acoustic bass or laptop mic?
Yes, but very low notes (like a bass low B or E) are hard for small laptop microphones to capture. If detection struggles, play the 12th-fret harmonic instead — it's the same note one octave up, rings clearly, and the tuner reads it much more reliably.
How often should I tune?
Every time you pick up the instrument. Tuning drifts with temperature, humidity, and playing — even overnight. Tuning before every session also trains your ear to notice when something sounds off.
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