Perfect fifths, an octave below viola
A cello is tuned C2–G2–D3–A3— the same perfect-fifth spacing as a violin or viola, shifted down an octave from viola’s C3–G3–D4–A4. It reads primarily in bass clef, switching to tenor and then treble as the part climbs into thumb position, but none of that changes what this tuner listens for: it names the sounding pitch regardless of which clef your part is written in.
Convention says tune the A string first, same as violin and viola: it is the string closest to the oboe’s orchestral reference pitch, and at A3 = 220 Hz — exactly one octave below a violin’s open A — it sits in the part of the tuner’s range that settles fastest. The other three strings are then checked against it.
Tune the A first, then D, G, C. Bow each string for two or three seconds rather than plucking — low strings need that long to settle into a steady reading, especially the C.
Pegs for the big moves, fine tuners for the last few cents
- Check all four strings first with the tuner above. If a string is close — within about a quarter tone — a fine tuner at the tailpiece can finish the job without touching a peg.
- For bigger drops, use the peg — while bowing constantly. Press the peg firmly into the pegbox as you turn (pegs hold by friction alone), sneak up to just below the target, then finish with the fine tuner.
- Give the C string real time. It is the thickest, highest-tension string on the instrument, wound rather than plain, and it visibly lags behind the other three after a peg move — bow it for several seconds before trusting the reading.
- Check the endpin before you blame the pegs. A cello stands on a spike planted against the floor, and pitch that drifts flat mid-phrase is very often the endpin slipping or the whole instrument rocking under bow pressure, not the tuning actually failing.
- Re-check the A after tuning the others. Four strings under real tension over a floating bridge shift each other more than a fretted instrument ever has to deal with, and the low C in particular can pull the bridge as it settles.
Sizing: fractions, not one fixed instrument
A full-size (4/4) cello is the standard for adult players, but — unlike a violin, where smaller sizes are mostly a student stepping stone — cellos are commonly built and sold down through 7/8, 3/4, 1/2, 1/4 and smaller, and a smaller-bodied cello is a completely normal permanent choice for a player with a shorter reach, not just a beginner size. None of that changes the target pitches above: C2 is C2 on any body size, tuned exactly the way this page describes. What changes is string length, the spacing between positions on the neck, and how much bow arm it takes to drive the lower strings.
Equal temperament vs. tuning by ear inside a chord
Like a violin or viola, a cello has no frets forcing it toward equal temperament — the open strings are conventionally tuned in pure, beat-free fifths by ear, which sit roughly 2 cents wider than the equal-tempered fifths this digital tuner reports. That is not a flaw in either method: use the tuner to set the A accurately against a concert reference, then tune D, G and C to it by listening for the beats between adjacent strings to disappear, which resolves more precisely than chasing a centred needle on each string in isolation. Once you are playing rather than tuning open strings, the same expressive-intonation logic applies as on any bowed instrument — thirds sit low, fifths sit high, relative to this equal-tempered grid — which our guide to cents covers in full.
Frequently asked questions
Is this different from the viola or violin tuner?
Same tuning engine, different targets. A cello is C2–G2–D3–A3 — exactly an octave below a viola’s C3–G3–D4–A4, and two octaves below a violin’s bottom string. The pegs, fine tuners and bowing technique are the same family of skill, but the frequencies are genuinely different, and this page reads them at the right octave instead of asking you to mentally shift a viola chart down.
Should I trust the tuner on the low C string?
Yes, but give it a beat. C2 is 65.41 Hz — low enough that a phone microphone and speaker both work harder to reproduce it cleanly than they do for the A string, and a thick wound string needs a moment of sustained bow pressure before the fundamental settles. Bow it steadily for two or three seconds rather than reading the first attack, and check the octave shown on the dial so a correctly-tuned C2 never gets mistaken for C3.
What is a wolf tone, and is it a tuning problem?
No — leave the tuner out of it. A wolf tone is the cello body resonating uncontrollably at one particular pitch, causing a warble or growl that no peg or fine-tuner adjustment fixes, because the string itself is at the correct pitch. It’s more common and more pronounced on cellos than violas, and on most instruments it lands somewhere between E and F♯ — you’ll usually meet it in first position on the D string or further up the G string, and it can be at its most stubborn when you reach that same pitch on the C string. The exact note is unique to each instrument’s body. A wolf-tone eliminator clamped to the string behind the bridge is the standard fix, not retuning.
My cello keeps going flat while I play, even though I just tuned it. Why?
Almost always the endpin — the metal spike planted against the floor — slowly sliding or the cello rocking on it under bow pressure, which changes the string angle over the bridge just enough to read as flat. Make sure the endpin has real grip (a rubber stop, a strap, or a floor with some texture) before re-tuning; re-tuning a symptom that’s actually a slipping endpin just repeats the problem a few minutes later.