Free Online Viola Tuner
Play an open string, see exactly how in tune you are.
A simplified preview of what the Tunable app does. Get the full app
Left to right: 4th string, the thickest, to 1st, the thinnest. Tune one string at a time.
Allow microphone access to begin
How to use this tuner
Click Start Tuning and allow microphone access. Bow a string, the tuner detects pitch in real time and shows how sharp or flat you are in cents.
The bar spans −50 to +50 cents. Zero is perfectly in tune. The history line shows where you’ve been, useful on the low C, which often wanders for a second before it centres.
The tuner reads against the nearest open string of Standard tuning (C3, G3, D4, A4), so the cents value is the distance to that string, not to the nearest chromatic note. Tap a string to hear its reference pitch and lock the tuner to it; tap again to release.
Viola is already selected. The viola is a concert-pitch instrument, it reads alto clef (switching to treble clef for high passages) and no transposition is applied, so written pitch and sounding pitch are the same.
Default is A440. Tap + / − to match your ensemble, A441–442 is common in orchestras, A415 for historical pitch.
The viola is a non-transposing, concert-pitch instrument. It is the standard home of the alto clef, moving to treble clef for sustained high passages, but in either clef the written note is the sounding note, no transposition is applied here, so the tuner shows exactly what you play.
The open strings are C3 (130.81 Hz), G3 (196.00 Hz), D4 (293.66 Hz), and A4 (440.00 Hz), a perfect fifth below the violin, sharing three of its four strings and replacing the violin’s high E with a low C. Set the A first against the tuner, then tune the remaining strings downward in fifths. Bowed double stops are the traditional check: a true fifth sounds perfectly still, while a fifth that is a few cents off beats slowly and audibly. Using the tuner for the absolute A and your ear for the fifths gives you both accuracy and a set of strings that ring together.
The C string is the viola’s particular challenge. It is a thick, low-tension string on a body that is acoustically too small for its pitch, every viola is, which is why they come in so many sizes, and it speaks slowly. Give it a slower bow with more weight closer to the bridge, and allow a full second before you trust a reading. The history display is genuinely useful here: the initial wobble as the string finds its mode is normal, and the plateau that follows is the pitch you want.
In an orchestra the tuning A comes from the oboe, usually A440, with many professional ensembles at A441 or A442 and period groups at A415. In a string quartet the first violin gives the A. Either way, set the reference control to match rather than tuning by feel, the difference between A440 and A442 is about eight cents, which is small enough to ignore individually and large enough to make a section sound muddy.
Common pitch problems fall into two groups. Bow-related: too much pressure with too little speed presses the string sharp, and a slackening bow near the tip lets long notes sag flat. Hand-related: because the viola’s string lengths are longer than a violin’s, players moving between the two instruments consistently place fingers too close together and end up flat in the upper half of the hand, half steps in particular need more space than the violin habit provides. Fourth finger is the usual casualty. Many violas also have a wolf tone, most often around F or F sharp on the C or G string, where the note breaks up and the tuner reading jumps: that is an instrument resonance, not your intonation, and it is addressed with a wolf eliminator or a change of bow contact point rather than with the pegs.
Tune with the bow, not pizzicato. The bow introduces the same pressure and speed variables you will face while playing, so a pitch that holds steady under the bow is a pitch you can actually rely on in the section.
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