Viola Tuner

How to tune your viola with this tuner

1. Start the tuner. Click Start tuner (or the big microphone button) and choose Allow when your browser asks for the microphone. Place your phone or laptop 30–50 cm (one to two feet) from the viola.

   

2. Play the A string first. Bow or pluck the open A string. The tuner recognises the string, shows the note, its frequency and how many cents it is off.
3. Follow the needle. Left of centre means flat — tighten the string. Right of centre means sharp — loosen it. The hint under the reading tells you which way to go, and the string you are tuning is outlined below the gauge.

   

4. Tune D, G and C. Work down from A, one string at a time. In the green zone (within 5 cents) the needle turns green and the string gets a check mark. If the tuner jumps between strings, click a string’s note to lock it, and click it again (or Auto-detect) to go back to automatic.

   

5. Check all four again. Changing one string shifts the tension on the others slightly, so go round once more.

Viola string notes and frequencies

A viola has four strings tuned in perfect fifths: C3, G3, D4 and A4, from lowest to highest. It shares its G, D and A strings with the violin but has a low C instead of the violin’s high E.

The values assume A4 = 440 Hz. If your orchestra tunes to 442 Hz, move the Reference pitch (A4) slider to 442 and every target updates. Pure fifths are about 2 cents wider than equal-tempered ones, so tuning down from A by ear leaves the C string about 6 cents below a piano’s C — choose Pure fifths from A if that is how you tune.

Pegs or fine tuners?

• Fine tuners are for small corrections of a few cents. Turn clockwise to raise the pitch and anticlockwise to lower it.
• Pegs are for bigger changes, such as new strings or a string that has dropped a semitone. Turn slowly while pushing the peg gently into the pegbox so it holds. Many violas only have a fine tuner on the A string, so the other strings are tuned with the pegs.
• If a fine tuner is screwed almost all the way in, back it out a few turns and bring the string up with the peg instead.
• Tune up to the note: if a string is sharp, take it slightly below the target and bring it back up. It holds its pitch better.
• After tuning, check that the bridge still stands straight and isn’t leaning towards the fingerboard.

Tuning by fifths with double stops

Once the A string is right, many violists tune the rest by ear: bow the A and D strings together and adjust D until the fifth sounds smooth, without a pulsing “wah-wah” beat. Then do the same with D and G, and with G and C. Use the needle to confirm each string, or click Tone under a string to hear its reference pitch until you click again.

How often should you tune?

Tune every time you play, and check again during long rehearsals — changes in temperature and humidity make strings and pegs move. New strings keep stretching for the first few days, so expect to retune them several times per session until they settle.

Viola tuner not working? Fix it step by step

1. Read the message on the tuner. If the status turns red and says Microphone access blocked, your browser or device is stopping the page from using the microphone. If it says Microphone is busy, another app is using it (go to step 4).

   

2. Allow the microphone in your browser. Click the icon to the left of the address bar, open Site settings (or Permissions) and set Microphone to Allow. Then reload the page and press Start tuner again.

   

3. Let your browser use the microphone. Windows 11/10: Settings › Privacy & security › Microphone — turn on Microphone access and Let desktop apps access your microphone. Mac: System Settings › Privacy & Security › Microphone — turn on your browser, then quit and reopen it. Android: Settings › Apps › Chrome › Permissions › Microphone. iPhone and iPad: Settings › Apps › Safari › Microphone (iOS 17 and earlier: Settings › Safari › Microphone) — choose Ask or Allow.
4. Close apps that may be holding the mic, such as Zoom, Teams, a recording app or another tuner app, then press Start tuner again. If you have more than one microphone, pick the right one in the menu at the top right of the tuner.
5. No clear note? If the tuner says We can’t hear a clear note yet, look at the Input bar. A long bar without a reading means noise or several strings at once: tune in a quiet room, bow one open string with a long, even stroke and stop the neighbouring strings from ringing. A short or grey bar means the mic hears too little: point it at the f-holes from 30–50 cm and raise the input volume in your system sound settings.

   

6. The needle jumps around or shows the wrong octave. Reduce background noise and keep the bow speed even; Pitch clarity under Signal details shows how clean the signal is. The low C has strong overtones, so a tuner can occasionally hear C4 instead of C3 — lock the C string, and readings one octave off are folded back to it.
7. Reference tone problems. Wear headphones if you play a tone while the tuner listens, otherwise it hears the tone instead of your viola. No sound on iPhone: switch off Silent mode and turn up the volume.

About this viola tuner

This free online viola tuner runs entirely in your browser with the Web Audio API. Pitch is measured on your own device with the McLeod pitch method; nothing is recorded, uploaded or stored, and your reference pitch and tone settings are remembered in this browser only.

It works on Windows, macOS, Linux, ChromeOS, Android, iPhone and iPad in current versions of Chrome, Edge, Firefox and Safari, with any microphone — from a laptop’s built-in mic to a clip-on instrument mic. No app or download needed.

Frequently asked questions