Chromatic tuner

A chromatic tuner does not aim at a set of strings. It takes the single note you play or sing, names the nearest of the twelve notes in the scale, and shows with a needle how far sharp or flat you are. That suits a trumpet, a flute, a recorder, a voice, or an instrument with an unusual tuning. Press Start the tuner and play one note.

The big letter is the note, with its octave beside it, and the pitch in Hz sits under the needle, for example 261.6 Hz. Sharps are written with a ♯, so a B♭ appears as A♯. There are no string buttons here, because no instrument is chosen, so there are no reference tones to play.

A worked example: you play a note on a B♭ trumpet that you read as a C. The page shows A♯, because it names the sound that comes out, not the written note. If the needle sits left of centre with “12 cents flat: tune up”, push the main tuning slide in a little to raise the pitch, and play again.

The twelve notes in one octave

Octave 4, from middle C, at A4 = 440 Hz in equal temperament. Each octave up doubles the frequency, so C5 is 523.25 Hz.

• C4 261.63 Hz, C♯4 277.18 Hz, D4 293.66 Hz, D♯4 311.13 Hz
• E4 329.63 Hz, F4 349.23 Hz, F♯4 369.99 Hz, G4 392.00 Hz
• G♯4 415.30 Hz, A4 440.00 Hz, A♯4 466.16 Hz, B4 493.88 Hz

What this page does not do

• It reads one note at a time. Chords, double stops and several players at once confuse it.
• It listens between about 30 Hz and 1,500 Hz, which is B0 up to F♯6. Notes outside that range are not read.
• It does not choose a string for you. For a guitar or a ukulele, the guitar tuner and ukulele tuner light the string you are tuning and play its reference note.
• It does not tune a piano. It can show how one note reads against its pitch, a single key at a time; it does not set a temperament.
• It shows the sounding pitch, not the written note, so transposing instruments read differently from their music.