Viola Tuner

How to tune your viola online

1. Choose your tuning.

   Pick Standard CGDA, or an alternate tuning like Open C, Fiddle, or Baroque.

2. Click "Start Tuning."

   Allow microphone access when your browser asks.

3. Bow or pluck the A string first.

   Most violists tune A to 440 Hz first, then use it as the reference for the rest.

4. Watch the meter.

   Turn the tuning peg for large adjustments, or the fine tuner for small ones, until the needle centers.

5. Tune D, G, and C, then recheck all four.

   Tuning one string can slightly shift the others, so a final pass over all four strings is always worth it.

How this tuner detects pitch

When you bow or pluck a string, this tool analyzes the sound through your microphone using an autocorrelation algorithm — it compares the waveform against slightly delayed copies of itself to find the point where they line up most closely, and that lag reveals the exact frequency you're playing. This runs entirely in your browser via the Web Audio API; your microphone audio is never recorded, uploaded, or sent anywhere, and it disappears the instant you close the tab.

Troubleshooting a jumpy or inaccurate reading

The needle won't settle, or jumps between notes

Background noise is the most common cause — a fan, a TV, or other instruments ringing nearby all confuse pitch detection. Mute any strings you're not testing and play a single, clean note rather than a chord.

It picks the wrong string

In Auto mode, a string that's very badly out of tune can land closer to a neighboring string's target pitch than its own, so the tuner locks onto the wrong one. Switch to manual string selection until it's roughly in range, then Auto mode will track it correctly from there.

Nothing registers at all

Check that microphone permission was actually granted — look for a blocked-mic icon in your browser's address bar — and confirm you're playing firmly enough for the microphone to pick up a clear signal above any background noise.

Standard viola tuning, and why it's built on fifths

Standard viola tuning is C3, G3, D4, A4 — written CGDA from the lowest string to the highest. What makes this arrangement distinctive is the interval between each neighboring pair: every string sits a perfect fifth from the one beside it. That's the interval that gives the violin family its characteristic resonance, lets double-stops ring cleanly, and is exactly why the traditional "tune in fifths" method (checking two adjacent open strings together and listening for that ringing harmony) works as a genuine tuning technique in its own right, independent of any tuner.

Pegs vs. fine tuners

A viola has two completely different mechanisms for adjusting pitch, and knowing when to use each makes tuning far less frustrating. The tuning pegs in the scroll's pegbox handle large adjustments — turning the whole peg noticeably changes pitch, which is exactly what you need when a string is well off target, but it's also easy to overshoot with. The fine tuners, small screws mounted on the tailpiece, move in tiny increments for the final precise adjustment once a peg has gotten you close.

Because fine tuners can only shift pitch by a few notes in either direction, it's very difficult to break a string using them, which makes them especially useful for beginners who tend to overturn a peg and go wildly out of tune. As you gain experience with the pegs themselves, some players remove fine tuners from certain strings, but that comes down to personal preference — use the peg to get close, then the fine tuner to land it precisely.

Alternate viola tunings

This tool covers Standard, Open C, Fiddle, and Baroque directly. For any other alternate tuning, or to tune to a completely custom note, our Chromatic Tuner listens for all 12 notes rather than a fixed set of strings.

What's the difference between a viola and a violin?

The viola is the middle child of the violin family, sitting between the violin and cello — its mellow alto voice tuned a fifth below the violin and a full octave above the cello. Beyond tuning, a viola is noticeably heavier and longer, calls for a different bowing technique built around arm weight rather than arm force, and requires stretching your fingers further across the fingerboard. It also uses its own alto clef rather than the violin's treble clef, so switching between the two instruments means learning to read music differently as well as relearning finger positions.

There are upsides too: because the viola's notes sit in a lower register, it's often easier to produce a good tone early on compared to a violin, and the longer string length gives harmonics a bit more margin for error when you're first learning to find them.

Fixing slipping pegs

A peg that won't hold its position is almost always a friction problem, not a broken instrument. Pegs and their holes rely on a snug friction fit to stay put, and that fit gradually loosens as temperature and humidity shift over time. Pushing the peg in firmly while turning it is a reasonable temporary fix, but doing this repeatedly can eventually wear the hole further. A more lasting solution is peg drops or peg compound, applied directly to the peg where it meets the pegbox — these products are specifically formulated to restore the right amount of grip without making the peg stick or squeak. In a pinch, a bar of soap rubbed lightly on the peg can work similarly. If slipping continues after that, it's worth having a luthier check whether the pegs or their holes need to be refitted.

More tools on ProDeviceTest

Practicing music rather than just tuning up? These run the same way — instant, no download, right in your browser.

• Violin Tuner — a perfect fifth higher, same scroll-and-pegbox design
• Cello Tuner — an octave lower, same scroll-and-pegbox design
• Guitar Tuner — standard 6-string tuning with an interactive headstock
• Chromatic Tuner — tune any instrument to any of the 12 notes
• Metronome — practice with a steady, accurate beat
• Pitch Detector — see the note, Hz, and cents deviation of any sound
• All Instrument Tuners — the full category