Free Guitar Tuner Online
A guitar tuner online listens through your microphone, estimates the pitch of each string, and shows whether that string is flat, sharp, or in tune. Use this free guitar tuner for standard tuning, drop D, half-step down, open G, ukulele, reference tones, and A4 calibration.
Built for music practice and game nights
Tune before practice, rhythm games, party performances, camp songs, school music sessions, and board game cafe events.
Find board games with GameShelfTuner
Use your microphone for live pitch detection or play a reference tone for the selected string.
Frequently asked questions
What is an online guitar tuner?
An online guitar tuner is a browser tool that listens to a string through your microphone, estimates its pitch, and shows whether the string is flat, sharp, or in tune.
What tuning does a guitar use by default?
Standard guitar tuning from lowest string to highest string is E2, A2, D3, G3, B3, and E4.
How close is close enough when tuning guitar?
Most players treat a string within about 5 cents of the target note as in tune. For recording or ensemble playing, get as close to zero cents as possible.
Can I tune without microphone permission?
Yes. Use the reference tone button to hear the selected string pitch, then tune by ear. Microphone permission is only needed for live pitch detection.
What does A4 calibration mean?
A4 calibration sets the reference pitch for the tuner. Most modern tuning uses A4 at 440 Hz, but some groups use nearby values such as 442 Hz.