AudioKitHow it works
Press Start microphone and allow access in your browser. Play one sustained note, let it settle and watch the pitch display. A negative cents value means the note is flat; a positive value means it is sharp. The central zone is within five cents of the nearest equal-tempered note. The instrument selector changes the available reference notes; detection itself remains chromatic. Click a reference button to hear that pitch briefly.
Formula
Reference frequency = A4 × 2^((MIDI note − 69)/12). One semitone is 100 cents, and an octave is 1,200 cents. Adjust A4 between 430 and 450 Hz to match the tuning reference you are using. Detection is designed for roughly 40–1,500 Hz.
Example
Standard guitar reference notes are E2, A2, D3, G3, B3 and E4. Standard four-string bass uses E1, A1, D2 and G2. High-G ukulele uses G4, C4, E4 and A4. These are reference tones, not alternate-tuning presets or automatic string selection. The tuner does not record, upload, or play microphone input through the speakers. Press Stop microphone to release access.
Assumptions and limitations
Use one clear sustained note for tuning. Noise, harmonics, room acoustics and microphone quality can affect the reading. Reference tones and clicks may be picked up by the microphone; use headphones when combining tools. This is a browser practice aid, not a calibrated measurement instrument.
Frequently asked questions
Do I need an account or an app?
No. The tools run in a modern browser. Audio starts from a button press, and the tuner needs microphone permission on HTTPS or localhost.
Is microphone audio recorded or uploaded?
No. Audio is analyzed locally in memory. It is not recorded, uploaded or played back through the speakers.
What happens when I leave the tab?
The metronome and tones stop, the microphone is released and the session timer pauses. Start again when you return.