Online cello tuner

Play a string and the tuner recognises which one it is, tells you whether it is flat or sharp, and turns green once it is in tune. Free, in your browser, nothing to install.

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± 0 ¢— Hz

Tap “Turn on microphone” and play a note.

Sound is analysed on your device. Nothing is recorded or sent anywhere.

Notes and frequencies for each tuning

Standard tuning for cello is Standard (CGDA): C2 G2 D3 A3, from string 4 to string 1. These are the exact frequencies with A at 440 Hz; change the reference in the tuner and they are recalculated.

Standard (CGDA)

StringNoteFrequency (A = 440 Hz)
4C265.41 Hz
3G298.00 Hz
2D3146.83 Hz
1A3220.00 Hz

How to tune, step by step

  1. Tap “Turn on microphone” and allow access. On a phone, keep it near the instrument, pointing at the f-holes.
  2. Play the open string with a long bow and medium pressure; pizzicato also works, but the note dies away sooner.
  3. Use the fine tuners on the tailpiece for small adjustments, and the peg for big ones, pushing it in as you turn so it does not slip. If you overshoot, go below the note and come back up.
  4. When it turns green the string is within ±5 cents. Tune the A first, then the rest, and check the open fifths by playing two strings together.

Sound Tools, the app

The same tuner on iPhone, Apple Watch and Android, offline, with an instrument catalogue and every string turning green within ±5 cents. Plus a metronome, a spectrum analyzer and a chord and key detector. Free, no account.

Get it on Google Play Download on the App Store

Frequently asked questions

What is the standard tuning for cello?

Standard (CGDA): C2 G2 D3 A3, from string 4 to string 1, with the reference A at 440 Hz.

Does it work with my phone’s microphone?

Yes. It works in any current browser — Chrome, Safari, Firefox or Edge — on Android, iPhone or desktop. It only needs permission to use the microphone.

Is my audio recorded or sent anywhere?

No. The analysis runs in your browser and the sound never leaves your device.

Can I tune to 442 or 432 Hz?

Yes: change the “A =” field and every string is recalculated. Anything from 400 to 480 Hz works.

Is there an app to tune offline?

Yes: Sound Tools for iPhone, Apple Watch and Android, free and without an account. It has these same tunings plus a metronome and a chord detector.

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