Free browser tuner
Best Cello Tuner? Free Strobe App for CGDA & Low C
Why the best cello tuner is a strobe
A bowed cello string sustains for the length of the bow stroke and carries a rich, stable harmonic spectrum - ideal input for a strobe. The pattern settles and the cents reading is rock-steady, far more so than on a plucked note. On the low C string this matters most: a needle tuner hunting by whole cents on a 65 Hz fundamental reads jitter; StroboPro gives every harmonic its own smooth rotating ring, so the fundamental and its partials show together and you can see when the string is genuinely in tune.
CGDA, one octave below the viola
The cello is tuned C2, G2, D3, A3 (CGDA), exactly one octave below the viola and two octaves below the violin's middle strings. Adjacent strings are a perfect fifth apart, so players tune A first, then D, G, and C against it, listening for beats in the fifths rather than reading each string in isolation. StroboPro's 0.1-cent reading is steady enough to leave on a stand while you bow each string.
How to tune a cello with StroboPro
- Open the cello tuning - tap the Tap to Tune button (the one with the microphone) and allow microphone access.
- Tune the A string first, to a 440 Hz reference (or 442 Hz if your orchestra plays sharp).
- Bow the A with a long, even downbow, no vibrato, until the harmonic rings stop moving.
- Tune D to A, then G to D, then C to G. Bow each pair as a double-stop to confirm the fifth is pure.
- Avoid vibrato while checking pitch - it modulates the note by several cents and makes any tuner read an average.
Free and offline
StroboPro runs free in a browser with no install, and the web tuner installs as a Progressive Web App so it works on a stand in a practice room or pit with no network. CGDA and scordatura presets are all included; there is no metering cap or trial timer.
Read "What is a strobe tuner and how does it work?" on the blog →Related guides
Frequently asked questions
What notes is the cello tuned to?
The cello is tuned C2, G2, D3, A3 (CGDA) - one octave below the viola. StroboPro ships a Cello preset with those exact targets; it is also fully chromatic for scordatura like the Fifth Suite's scordatura tuning. Open it directly: [cello standard tuning](https://strobopro.se/preset/cello/4-string/standard).
Why is the low C string hard to tune?
C2 sits around 65 Hz with strong overtones, which confuse cheap pitch estimators. Each harmonic gets its own rotating ring, so the fundamental and its partials show together and you can read a stable cents value instead of a jittering needle. That low-end steadiness is where a strobe display earns its keep over a needle.
Support independent development with premium access
I’m an independent developer, and I keep the core StroboPro tuner free. Premium access to features such as cloud sync, AI tuning generation, and the custom tuning editor helps cover backend infrastructure and the tools I need to keep developing and supporting StroboPro.
You can try the full version during a no-strings-attached trial. The trial never converts automatically: when it ends, premium features are simply disabled until you actively choose an affordable subscription or a one-time purchase for lifetime premium access. The one-time purchase is available on iOS and Android, like buying the app outright; web one-time purchase support is coming soon.
Published by Applicaudia, the maker of StroboPro. Resolution figures describe the on-screen display, not lab-measured accuracy specifications. Reference pitch (440 vs 442 Hz) and interval choices vary by ensemble and tradition.
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