Professional Instrument Tuner
Tune your guitar, bass, or ukulele using your device's microphone. Fast, accurate, and free.
Reference Notes
The Musician's Tuning Guide
How it Works
This tuner uses Auto-Correlation algorithms to analyze audio waves from your microphone. It calculates the fundamental frequency of your string and compares it to the standard A440 pitch reference used worldwide.
Tuning Tips
For the best accuracy, pluck the string firmly but not aggressively. Mute the other strings with your hand to prevent sympathetic vibrations from confusing the sensor. Tuning in a quiet room is highly recommended.
Why 440 Hz?
The standard "Concert Pitch" for the note A4 is 440 Hz. This was established as the international standard in 1939 to ensure that instruments from different manufacturers can play together in perfect harmony.
Tuning accurately with a microphone tuner
This tuner listens through your device microphone, detects the fundamental pitch of the note you play, and shows how far it sits from the target in cents. A cent is one hundredth of a semitone, and most listeners begin to notice a discrepancy somewhere around five cents.
Getting a reliable reading
Play a single open string cleanly and let it ring. Detection needs a sustained fundamental, so a hard pick attack, a muted string or two notes sounding together will produce a reading that jumps around.
Work somewhere reasonably quiet. Background music, a television or a nearby conversation all feed into the microphone and confuse pitch detection. Position the instrument close to the microphone, but not so close that the signal distorts.
Low strings are the hardest to read. The bottom E on a guitar sits around 82 Hz, and a short sample of a low frequency gives the detector fewer cycles to work with, so give those strings a little longer to settle.
Tuning technique that holds
Always approach the target pitch from below. A string tuned downwards into position leaves slack in the windings and at the nut, which slips back out of tune as you play. If you overshoot, drop well below and come back up.
Tune all six strings, then tune them again. Changing the tension on one string alters the pull on the neck and detunes the others slightly, so the second pass is genuinely necessary rather than pedantry.
Fret the twelfth harmonic and compare it with the fretted note at the same position. If they disagree consistently, your intonation needs adjusting at the bridge rather than at the tuning peg, and no amount of retuning will fix it.
Standard reference
Concert pitch sets A above middle C at 440 Hz, which is the assumption here and on nearly all modern recordings. Some orchestras tune to 442 or 443, and historically informed ensembles often use 415 for baroque repertoire.
New strings need patience
Fresh strings stretch for the first hour of playing. Tune, stretch gently by hand, and retune several times.
Temperature moves pitch
A cold instrument brought into a warm room will drift. Let it acclimatise before a careful tuning.
Check your intonation
If open strings read true but chords sound wrong up the neck, the bridge saddles need setting, not the tuners.
Frequently asked questions
Why does the reading keep jumping around?
Usually background noise, an overtone-rich attack, or more than one string ringing. Mute everything else, play one note softly and let it sustain.
Can I tune a ukulele or bass with this?
Yes. It detects pitch chromatically rather than assuming a particular instrument, so any pitched instrument works. Very low bass notes need a longer sustained sample.
What does the cents reading mean?
A cent is one hundredth of a semitone. Within about three cents of zero is comfortably in tune for most playing situations.
Do I need to allow microphone access?
Yes. The tuner cannot hear anything without it. Audio is analysed in your browser and never transmitted or recorded.