Instrument Tuner - Chromatic Tuner in Your Browser

How to use this tool

1. Click "Start Tuner" and grant microphone access when prompted.
2. Play a note on your instrument. The detected note, octave, and cents offset appear.
3. Tune until the cents bar is centred at 0.

Concert pitch (A440)

The international standard concert pitch is A4 = 440 Hz, codified in ISO 16:1975. This means the note A above middle C vibrates at 440 cycles per second. Not everyone uses this exact frequency in practice: many orchestras tune to A442–A444 Hz for a brighter, more resonant sound (especially common in European ensembles). Early music ensembles often use lower pitches (A415 or A432) to match historical instrument tuning.

Tuning systems

The way the 12 notes of the octave are spaced apart constitutes a tuning system:

• Equal temperament (modern standard): divides the octave into 12 equal semitones of exactly 100 cents each. Every key sounds equally in tune (or equally "out of tune") - this is why it became the standard for pianos and most modern instruments.
• Just intonation: uses small whole-number frequency ratios (e.g., perfect fifth = 3:2). Produces pure, beatless intervals in one key but intervals in other keys sound noticeably wrong.
• Meantone temperament: a historical compromise that makes common keys sound better than equal temperament at the cost of dissonant remote keys (the "wolf" intervals).

Cents

A cent is 1/100th of a semitone. There are 1,200 cents per octave in equal temperament:

• ±2–3 cents: excellent intonation; most trained listeners cannot detect this
• ±5 cents: generally imperceptible to most non-musicians
• ±10–15 cents: noticeable to trained ears, especially in ensemble contexts
• ±20+ cents: clearly audible to most listeners; instrument needs tuning

How pitch detection works

The tuner captures audio from your microphone and analyses it using autocorrelation - a technique that finds the repeating period of the waveform, which corresponds to the fundamental frequency (pitch) of the note.

Tuning tips

• Use in a quiet environment for best accuracy.
• Hold the note steady - the reading stabilises after a moment.
• Tune until the cents indicator is near 0 and the bar is green.

Privacy

All audio processing happens locally in your browser. No audio data is recorded, stored, or transmitted to any server.