Instrument Tuner
Chromatic tuning for strings, brass, woodwind and voice
Your browser will ask for microphone permission. The audio is analysed in this page.
How it works
- Enable the microphone and allow the browser prompt.
- Play a single note and hold it steady.
- Adjust the string or peg until the needle sits at 0 cents.
ABOUT THIS TOOL
Free Online Chromatic Tuner
Play a note and the tuner shows its name, frequency and how many cents sharp or flat it is. It listens through your microphone and works for any instrument with a steady pitch, including your voice.
- Output
- A live readout rather than a file: the note name in large type, the nearest note's exact frequency, your measured frequency, and how many cents sharp or flat you are. The needle shows the same offset on a ±50 cent scale, and the values turn to the primary colour once you are inside five cents. The microphone stream is analysed in the page and stopped when you leave.
How it works
- 01Press Enable microphone and allow the browser permission prompt.
- 02Play a single note close to the microphone and hold it steady.
- 03Adjust the string or tuning peg until the needle sits at 0 cents.
Key features
- Chromatic note detection — no instrument preset needed
- Note name, exact frequency and ±cents offset
- YIN pitch detection in the browser, running on the microphone stream in the page
- No sign-in and no per-use cost
Settings explained
- Frequency
- Your measured frequency in hertz, shown to one decimal place, with the nearest note's reference frequency beside it. A4 is fixed at 440 Hz, so a reading of 441.5 Hz against A4 reads about +6 cents.
- Reference: A4 = 440 Hz
- The tuning reference: A4 = 440 Hz, the international standard and the default in most DAWs, samplers and orchestral practice. Because the tuner is chromatic rather than preset-driven there is no list of instruments to pick from — it names whichever of the twelve notes you play.
- Enable microphone
- Starts and stops microphone capture. The browser asks for permission the first time; if it is denied, the page says so explicitly rather than showing a needle that never moves. Capture stops when you press Stop or leave the page, and every media track is closed so the browser's recording indicator goes out.
How the pitch is detected
Every frame of microphone audio is analysed with the YIN estimator through Essentia.js rather than a hand-rolled autocorrelation. The estimator runs on a 4096-sample frame, which at 44.1 kHz is a window of about 93 milliseconds — long enough to lock on to a low bass note, short enough to follow a moving pitch. Input is limited to 55–1600 Hz, the range that covers the fundamental of voices and common instruments, and frames are analysed twenty times a second, which is responsive without burning a core on roughly 100,000 operations per frame. A frame with an RMS below 0.008 is treated as silence and skipped entirely, which stops the estimator from reporting room noise as a note, and a frame whose confidence falls below 0.5 is discarded rather than displayed. Automatic gain control, echo cancellation and noise suppression are all turned off for the capture, because those processors are tuned for speech and will flatten a sustained instrument note.
What the cents readout tells you
A cent is one hundredth of a semitone, so 1200 cents make an octave. The nearest note is found by rounding the measured pitch to the closest semitone, and the difference between the two is reported in cents: positive means sharp, negative flat, zero means in tune. The needle spans −50 to +50 cents, which is exactly the distance to the neighbouring semitones, so a reading at either end means the note is closer to its neighbour than to the note displayed. Within a few cents of zero is in tune for practical purposes; the readout is rounded to whole cents, and being inside five cents lights the display.
Getting a stable reading on a real instrument
Pitch detection is only as good as the note it hears, and a plucked or struck note changes pitch as it decays, so the most reliable habit is to play the note, let the attack settle and read the display a moment later. Placing the microphone closer to the instrument than to a room's reflections helps more than any setting on this page, and a very noisy room makes detection slower and the reading jumpier. Wind and brass players usually get the steadiest result from a sustained note at a comfortable dynamic rather than a loud one, because the pitch of a loud attack can sit sharp of the sustained note. Voice works the same way: a steady sung note with the mouth a hand's width from the microphone reads cleanly, and vibrato will show as a needle that swings rather than a single value.
Common questions
Yes. The tuner listens through your device microphone and the browser asks for permission the first time. The audio is analysed in the page.
Anything that produces a steady pitched note: guitar, bass, ukulele, violin, cello, brass, woodwind, and the human voice. A very noisy room can make detection slower.
A cent is one hundredth of a semitone. 0 cents means the note is in tune; a positive value is sharp and a negative value is flat. Aim for within a few cents of zero.
Accurate to the resolution it displays: notes are located to the nearest semitone and the offset is reported in whole cents, so the readout is as precise as most electronic tuners. What varies is the input rather than the maths — a steady sustained note reads stably, while a decaying plucked string, a wide vibrato or a noisy room will move the reading around. For a fixed reference, play the same note more than once and check that the readings agree.