Pitch Detector

Play a note into your microphone and see its frequency, nearest note and cents offset.

Detect the note being played

Detected frequency: —

Nearest note: —

Cents from that note: —

Input level: —

Status: Microphone idle

Pitch comes from autocorrelation of the microphone signal, so a quiet room and one clear note give the steadiest reading.

Common questions about the free online pitch detector.

Click Start listening, allow microphone access and play a single steady note. The tool shows the frequency, the nearest note and the cents offset.

It runs autocorrelation over the microphone samples to find the repeating period of the waveform, then converts that period into a frequency.

One semitone is 100 cents. A reading of plus 20 means you are 20 cents sharp of the nearest note, and minus 20 means you are flat.

Room noise, vibrato and quiet playing all confuse autocorrelation. Play one clear note, hold it steady and reduce background sound.

Monophonic sources work best, such as a voice, guitar, violin, flute or a single piano note. Chords and drums do not give a stable pitch.

It reports notes between about 40 Hz and 2000 Hz, which covers bass instruments up to the top of a soprano voice and most woodwind.

No. The samples are analysed frame by frame in memory to find the pitch and are never recorded, stored or uploaded anywhere.

Yes. Any modern mobile browser that supports microphone access will work, and most phones pick up instruments well from a metre away.

Last updated: October 10, 2026