Free online tool
Chromatic Tuner: Free Online Tuner for Any Note, A4 415–466 Hz
Free chromatic tuner online: shows the nearest note, octave, frequency and cents for any instrument or voice via your microphone. Set A4 from 415 to 466 Hz.
Press the button and your browser will ask to use the microphone. The tuner needs it to hear your instrument. Sound is analysed on your device and is never recorded or sent anywhere.
About the Chromatic Tuner
A chromatic tuner listens to one note at a time through your microphone, names the nearest of the twelve notes and shows how many cents sharp or flat it is. This free chromatic tuner runs in your web browser with no sign-up, so there is nothing to install. It works for any instrument or voice, from a guitar pitch tuner or piano note finder to a vocal note detector. You can also set the A4 reference anywhere from 415 to 466 Hz, which helps when you tune to an orchestra or to Baroque pitch. Nothing you enter is uploaded.
How to use the Chromatic Tuner
- Press Start microphone and allow access when the browser asks.
- Set A4 reference (Hz) to the reference you need. 440 Hz is the modern standard.
- Play or sing one note and let it sustain. Keep the microphone away from other sound sources.
- Read the display. It shows the nearest note, its octave, the frequency and how many cents sharp or flat you are.
- Adjust your instrument until the needle sits in the green centre band and the display says In tune.
To hear a reference, choose a note in the Reference note box and press ▶ Play. It plays a pure tone, and the box covers C2 to C6. This makes the tool useful as a note finder guitar players can use while tuning by ear.
Play one note at a time and let it ring. Chords or overlapping notes make the reading jump between pitches, so pluck or bow one string, wait for the sound to settle, then check it.
Keep the microphone away from other sounds, such as a TV, a fan or another instrument. Background noise can make the display stay blank.
If you need a reference pitch, use the Reference note box and press ▶ Play to hear any note from C2 to C6 as a pure tone.
Read the cents value as a direction. Negative means flat, so tune up. Positive means sharp, so tune down. The meter runs from −50 to +50 cents.
What is a chromatic tuner?#
A chromatic tuner recognises all twelve notes of the octave, not just the open strings of one instrument. It names the nearest note and shows how far above or below it your pitch is. That is why one tool can check a guitar, a bass, a sax or a sung note.
What does A4 = 440 Hz mean?#
A4 = 440 Hz is the reference pitch. The A above middle C vibrates 440 times per second, and every other note is calculated from it. With A4 at 440 Hz, a note with MIDI number n has the frequency 440 × 2^((n − 69) / 12). This gives middle C (C4) at 261.63 Hz and A3 at 220.00 Hz. Some orchestras use 441–443 Hz, and Baroque ensembles often use 415 Hz. Changing the reference shifts every note, so set it before you tune.
How does the tuner find the note?#
The tuner takes short slices of the microphone signal and estimates the fundamental frequency with an autocorrelation method, the McLeod pitch method as implemented in the open-source pitchy library. It then turns the detected frequency f into 69 + 12 × log2(f / 440), rounds that to the nearest note, and reports the remainder. Quiet frames and unclear, noisy ones are ignored, so the display stays blank until a clear pitch is heard.
How are cents calculated?#
Cents = 1200 × log2(f / fnote), where f is the detected frequency and fnote is the frequency of the nearest equal-tempered note at your chosen A4. One cent is one hundredth of a semitone. Negative values are flat and positive values are sharp, and the meter shows −50 to +50 cents. The display says In tune when the pitch has stayed within 5 cents of the note for about a third of a second.
What range of notes can it detect?#
The tuner detects roughly 25 Hz to 2200 Hz. That range covers the low B of a 5-string bass (30.87 Hz) and every open string on the instrument tuner pages. Very low notes need a microphone that reproduces bass well, so a laptop or phone microphone may struggle with the lowest strings.
Can I tune my voice with it?#
Yes, within limits. The tuner shows the pitch of a steadily sung vowel. Voices wobble more than plucked or bowed strings, so the reading moves around the note. Hold a single vowel and watch the average position of the needle rather than each small movement.