ToneToolkit

Online Tuner

Tune any instrument with your microphone.

Everything runs in your browser. No audio is ever uploaded.

Microphone access needed

Allow microphone access so the tuner can listen to your instrument. Audio stays on your device and is never uploaded.

Instrument

A4 reference

Hz

Audio starts on your first tap on Play, as required by your browser.

This online tuner listens through your microphone and tells you two things: which note you just played, and how far off it is in cents. It covers guitar, bass, ukulele and violin with string presets, plus a chromatic mode that names any note between 28 and 2100 Hz, and the reference pitch moves anywhere from 415 to 466 Hz. Nothing is recorded and nothing leaves your device.

Popular presets

How to use it

  1. Press Enable microphone and accept the browser prompt. If you are on a laptop, the built-in microphone is usually good enough; the tuner needs pitch, not fidelity.
  2. Pick your instrument. The guitar, bass, ukulele and violin presets list the target strings with their exact frequencies and highlight the string closest to what you are playing, so you always know which one the tuner thinks you mean. Chromatic mode drops the targets and simply names whatever it hears.
  3. Play one string on its own and let it ring. Damp the strings you are not tuning with the side of your hand. More than one note sounding at once is the single most common reason a tuner jumps around, and the page says Signal unclear when that happens.
  4. Read the big note name and the needle underneath. The scale runs from 50 cents flat to 50 cents sharp, and the marker turns green with In tune inside 5 cents. A positive number means the string is sharp and needs loosening; a negative number means it is flat and needs tightening.
  5. Change the A4 reference if you need to. The buttons give 432, 440 and 442 Hz, and the box and slider take any value from 415 to 466 Hz. Every target on the page moves with it, so a preset tuned to 442 Hz stays internally consistent.

What you can use it for

Tuning a guitar or bass before you play. Work from the lowest string up, then go around a second time, because tightening one string changes the tension on the neck and pulls the others slightly with it.

Alternate guitar tunings by ear. The presets cover standard tuning only, so switch to Chromatic and aim for the note names yourself: drop D lowers the sixth string from E2 to D2 at 73.42 Hz, half a step down puts every string on the note below it, and DADGAD reads D2, A2, D3, G3, A3, D4 from low to high. Chromatic mode names whatever it hears, so the note name is your target instead of a highlighted preset.

Checking intonation rather than tuning. Tune the open string, then play the same string fretted at the twelfth fret. If the fretted note reads consistently sharp or flat by more than a few cents, the saddle position is off rather than your tuning.

Matching another instrument or an ensemble. Many orchestras tune to 442 Hz, some to 443 Hz, and historically informed groups often use 415 Hz, a whole semitone below modern pitch. Set the reference first and everything else follows.

Checking a sung or recorded note. Chromatic mode names anything in range, so you can hold a note and watch how steady it is, or play back a recording near the microphone to see what key it sits in.

Standard tunings and their frequencies

InstrumentStrings, low to highFrequencies at A4 = 440 Hz
GuitarE2 A2 D3 G3 B3 E482.41, 110.00, 146.83, 196.00, 246.94, 329.63 Hz
BassE1 A1 D2 G241.20, 55.00, 73.42, 98.00 Hz
UkuleleG4 C4 E4 A4392.00, 261.63, 329.63, 440.00 Hz. The G is re-entrant, so it sits above the C rather than below it.
ViolinG3 D4 A4 E5196.00, 293.66, 440.00, 659.26 Hz, a perfect fifth apart all the way up.

Accuracy and limits

A microphone hears the whole room. Another instrument, a television or someone talking can pull the reading, and so can the other strings ringing in sympathy. Damp everything you are not tuning, get close to the microphone, and treat a wandering reading as a signal problem rather than a tuning problem.

The range is 28 to 2100 Hz, which covers the low B of a 5-string bass at 30.9 Hz and everything above it that you would tune an open string to. A very bright pick attack is dominated by harmonics for the first moment, so the note can flick an octave high before it settles. Wait for the sustain and read that.

Cents are measured against equal temperament at your chosen reference. Real instruments do not obey that exactly: a piano is deliberately stretch tuned so its extremes read sharp at the top and flat at the bottom, guitar intonation drifts across the neck, and players of fretless instruments adjust pitch by ear inside a chord. A reading a few cents off is information, not a verdict.

Frequently asked questions

How do I tune a guitar with this?

Choose the Guitar preset, play the low E string on its own and let it ring. The nearest target string lights up, the note name appears, and the needle shows how far off you are. Loosen if the reading is positive, tighten if it is negative, then move to the next string and repeat the whole set a second time.

What does cents mean on a tuner?

A cent is one hundredth of a semitone, so 100 cents is the distance from one fret to the next. Under about 5 cents is inaudible on most instruments, which is why the tuner calls that in tune. Past about 10 cents you will hear the beating against another instrument.

Should I tune to 440 or 432 Hz?

440 Hz is the international standard and what everyone else will be tuned to, so use it unless you have a reason not to. 432 Hz is a stylistic preference some people like the sound of; claims that it is healthier or more natural are not supported by evidence. Both buttons are here, and so is anything from 415 to 466 Hz.

Why does the detected note jump around?

Usually because more than one thing is sounding. Other strings ringing in sympathy, room noise, or a hard attack full of harmonics all confuse pitch detection. Damp the other strings, play a little softer, and read the note once it has settled into its sustain.

Does it work for a 5-string bass or a 7-string guitar?

Yes, though the presets show the four and six string layouts. The tuner reaches down to 28 Hz, which is below the low B of a 5-string bass at 30.9 Hz and below the low B of a 7-string guitar at 61.7 Hz. Use the bass or chromatic mode and tune the extra string to its note name.

Can I tune a piano with it?

You can check a piano, but you should not tune one with it. Piano tuning is stretched on purpose so that the top and bottom of the keyboard sit deliberately outside equal temperament, and the mechanical side of the job needs a technician with the right tools. Use this to find out how far a piano has drifted, then call someone.

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