Free Online Guitar Tuner
Play a string — see exactly how in tune you are.
Allow microphone access to begin
How to use this tuner
Click Start Tuning and allow microphone access. Play a string — the tuner detects pitch in real time and shows how sharp or flat you are in cents.
The bar spans −50 to +50 cents. Zero is perfectly in tune. The history line shows where you’ve been — useful for spotting whether a string drifts after you pluck it.
Guitar is set by default. Use the dropdown to switch to another instrument if needed — note names automatically adjust.
Default is A440. Tap + / − to match your ensemble — A441–442 is common in orchestras, A415 for historical pitch.
Standard guitar tuning — E2, A2, D3, G3, B3, E4 from low to high — gives you six reference pitches to check before you play. Even though plucked strings decay quickly, they drift over time as temperature changes, tuning pegs settle, or new strings stretch in. The pitch history display helps you spot these patterns: if the line consistently sits flat after you’ve tuned, the string may still be settling. For altered tunings — drop D, open G, DADGAD — the chromatic display always shows your actual pitch, regardless of what’s standard. Tune one string, hold it, and watch the history line: a stable horizontal trace means you’re done.
Want the complete experience?
The Tunable app adds 15+ tuning temperaments, metronome, tone generator, recording, ear training, and more — all on your phone.
