Cello Tuner Online
Bow a string and your microphone does the rest — the tuner names the string, tells you whether to raise or lower it, and checks off C, G, D, and A as they land. Free, no app, nothing recorded.
Tap a peg to hear its note and start tuning — the browser will ask for mic access once. Sound is analyzed on your device, never uploaded.
How to Tune a Cello Online
A to C, fifth by fifth, in about a minute.
Allow the Microphone
Press Tune my cello and grant mic access when the browser asks. The analysis never leaves your device.
Bow or Pluck a String
Start with the A, as orchestras do. A steady bow stroke gives the cleanest reading — the tuner names the string and shows the offset in cents.
Adjust Until It's Green
Follow the tune up / tune down hint — fine tuners for small moves, pegs for big ones. When the needle centers and holds, the string earns its check. Four checks and you're set.
Built for the Way Cellists Tune
Auto string detection, plain-language directions, green when done.
Hears Which String You Play
Bow or pluck any of the four strings and the tuner identifies it on its own — no cycling through C-G-D-A by hand. Tap a peg to lock one if you'd rather.
Sharp or Flat, in Plain Words
Instead of leaving you to interpret a needle, the readout says tune up or tune down — so you know whether to reach for the fine tuner or roll the peg, and in which direction.
Four Strings, Four Checks
Every string that settles within tolerance earns a check on its peg. One glance tells you whether the A is done and the C is still waiting.
A Reference A — and the Rest
Each peg plays its target pitch aloud. Sound the A3, tune it by ear the way orchestras do, then let the needle confirm the fifths below it.
Nothing Leaves Your Device
The mic feed is analyzed frame by frame right in your browser and thrown away. No audio is stored, uploaded, or kept — it listens, it doesn't record.
Phone, Tablet, Laptop
Prop your phone on the stand and tune before rehearsal — iOS, Android, Chrome, Firefox, Safari, and Edge are all covered.
It Listens — It Never Records
Everything the microphone hears is analyzed on your own device, frame by frame, and immediately discarded. No audio is stored or uploaded, and mic access ends the instant you press Stop.
No Recording
Frames are analyzed and discarded
No Upload
The analysis runs in your browser
You're in Control
Stop ends mic access instantly
Wherever a Cello Needs an A
From the practice room to the pit — anywhere with a browser.
Orchestra & Ensemble
Match the section's A before the conductor taps the stand
Lessons & Students
Plain up/down directions mean beginners tune without a teacher hovering
Recording Sessions
A minute with the tuner beats discovering a flat C in the mix
Home Practice
No pitch pipe, no piano needed — the reference tones live in your browser
Ear Training
Tune the fifths by ear first, then let the needle grade the interval
Any Cello, Any Setup
Acoustic or electric through a small speaker — one clear string is all it needs
Four Strings in Perfect Fifths
The cello is tuned C2 G2 D3 A3 — each string a perfect fifth above the last, the same interval layout as the viola but a full octave lower. The A string sits at 220 Hz, exactly one octave under the orchestra’s A 440, and the C string reaches down to 65.4 Hz, deep enough that many small speakers can barely reproduce it. Because the strings are locked in fifths, one sour string doesn’t just sound wrong on its own — it bends every double stop and drone that touches it. This tuner measures each string in cents against equal temperament and walks you to center.
Start from the A and work down
Orchestral habit is worth keeping at home: tune the A string first, then the D, G, and C in order. The A is the pitch the oboe gives the orchestra and the anchor everything else hangs from, so settling it first means the fifths below have a fixed reference. With auto-detection you can play the strings in any order you like — the tuner recognizes whichever one is sounding — but going A-down builds the habit that serves you the moment you sit in a section.
Fine tuners for inches, pegs for miles
The cello gives you two controls per string, and using the right one is most of the craft. If the readout shows a string just a few cents off, the fine tuner at the tailpiece is the tool — a quarter turn moves the pitch a hair. If a string has drifted far, or you’ve just fitted a new one, go to the peg: press it inward as you turn so it holds, overshoot slightly sharp, then ease back down and finish with the fine tuner. The tuner’s up/down hint applies to both — it tells you the direction, you choose the mechanism.
Making the low C register
A C2 at 65 Hz is the hardest note on the instrument for any microphone tuner — the fundamental is quiet and the overtones carry most of the energy. Two things fix it: proximity and sustain. Bring the cello close to your device, then either pluck the C firmly and let it ring or, better, draw a slow full bow stroke. Bowed long tones are the ideal signal — steady pitch, generous sustain — and they read almost instantly on every string. If the room is noisy, the same advice applies: closer and louder wins.
The rest of the string family
The same engine tunes the whole shelf: violin, guitar, bass, mandolin, and ukulele, each with its own string set and reference tones. To see the raw frequency of any note you play, the pitch detector reads it in hertz — and once you’re in tune, the online audio editor is ready to record.
Tuned Up? Roll Tape
The full Notevibes Online Audio Editor records your playing, cleans up room noise, detects key and tempo, and exports to MP3 or WAV — all in your browser.
Free to try · No credit card required
Related Audio Tools
More free AI audio tools from Notevibes — same engine, no sign-up.
Violin Tuner
Tune G D A E with your mic — bow or pluck.
Bass Tuner
Tune a 4-string bass (E A D G) with your mic.
Guitar Tuner
Tune all six strings with your mic — auto string detection.
Pitch Detector
Read the live pitch of any sound — Hz, note, and cents.
Note Identifier
Sing or play a note and see its name instantly.
Online Audio Editor
Multi-track browser editor with every tool built in.
Cello Tuner FAQ
How do I tune my cello with this online tuner?
Press the button, allow microphone access, and play a string — a steady bow stroke or a firm pluck both work. The tuner names the string, shows how far off it sits, and says tune up or tune down. Adjust until the needle centers and turns green, hold the pitch a moment, and the string gets a check. Four checks and the cello is done.
What notes is a cello tuned to?
C2 G2 D3 A3, low string to high, referenced to A4 = 440 Hz. The strings sit a perfect fifth apart — the same interval pattern as the viola, one octave lower. The A string rings at 220 Hz and the low C all the way down at 65.4 Hz.
Should I use the pegs or the fine tuners?
Both, for different jobs. Fine tuners at the tailpiece are for small corrections — a few cents sharp or flat. If the tuner shows a string far from its target, use the peg to get close, then finish with the fine tuner. Trying to make a big move with a fine tuner just runs it out of thread.
Is it better to bow or pluck while tuning?
A slow, steady bow stroke gives the tuner the cleanest possible signal — a long sustained tone with a stable pitch. Plucking works too and is handy for quick checks, but the note decays fast, so re-pluck as you adjust. Many cellists pluck to get close and bow to confirm.
Why is the low C string hard to read?
At 65 Hz, the C2 carries most of its energy in overtones, and small phone mics hear little of the fundamental. Get the cello closer to the microphone and either pluck firmly or bow a steady, full tone. A confident bow stroke close to the mic reads almost instantly.
Is anything recorded or uploaded?
No. The microphone signal is analyzed on your own device in real time and discarded frame by frame — nothing is saved or sent anywhere, and the mic shuts off the moment you press Stop.
Is it free?
Entirely free — no account, no download, no usage caps. It runs in your browser and asks only for microphone permission, which you can withdraw whenever you like.