Online Tuner: Guitar, Bass, Ukulele and Chromatic
Tune a guitar, bass, ukulele, violin, viola or cello with an online tuner that listens through the microphone in your phone, tablet or laptop. Pick an instrument and the guitar tuner, bass tuner or ukulele tuner names the string you played and says whether to tune it up or down; pick Chromatic and it names any note, for any instrument. A4 can be set anywhere from 415 to 466 Hz, every string has a reference tone, and nothing you play leaves your device.
Before you start: play one string at a time, let it ring and keep the others quiet. A reading appears only when the note repeats cleanly, so silence, talking and chords show nothing.
Press Start and allow the microphone when your browser asks.
– – cents Start the tuner, then play a note Reference tones Each button plays its note for four seconds, rich in harmonics so a phone speaker that cannot reach a bass string's fundamental still sounds its pitch. The tuner pauses while it plays; press it again or Esc to stop. The tuner reads from 27 Hz to 4.5 kHz, which takes in a five-string bass's low B and the top of a piano. To play a note to tune by ear instead, use the tone generator's note picker; to check what the microphone itself picks up, run the mic test.Tune your instrument
How to read the tuner
Standard tunings and their frequencies
Each instrument's strings in standard tuning, in the order they are named (a guitar from its low E to its high E, a ukulele from its G to its A), with each string's equal-tempered frequency at A4 = 440 Hz. These are the notes and frequencies the tuner's instrument settings aim at.
| Instrument | Strings and their frequencies (Hz) |
|---|---|
| Guitar, standard | E2 82.41, A2 110.00, D3 146.83, G3 196.00, B3 246.94, E4 329.63 |
| Guitar, drop D | D2 73.42, A2 110.00, D3 146.83, G3 196.00, B3 246.94, E4 329.63 |
| Bass, 4-string | E1 41.20, A1 55.00, D2 73.42, G2 98.00 |
| Bass, 5-string | B0 30.87, E1 41.20, A1 55.00, D2 73.42, G2 98.00 |
| Ukulele (high G) | G4 392.00, C4 261.63, E4 329.63, A4 440.00 |
| Ukulele (low G) | G3 196.00, C4 261.63, E4 329.63, A4 440.00 |
| Violin | G3 196.00, D4 293.66, A4 440.00, E5 659.26 |
| Viola | C3 130.81, G3 196.00, D4 293.66, A4 440.00 |
| Cello | C2 65.41, G2 98.00, D3 146.83, A3 220.00 |
How a tuner hears a note
A plucked or bowed string vibrates at one frequency and at whole-number multiples of it at the same time: the fundamental, which sets the note, and the harmonics above it, which make a guitar and a violin on the same note sound different. All of them line up again after one period of the fundamental, so the whole sound repeats at the fundamental's rate, and that rate is the pitch we hear.
A tuner measures the rate. This one compares the last fraction of a second of sound with itself shifted in time, finds the shortest shift at which it lines up again, which is one period, and turns the period into a frequency, then into the nearest note and how many cents away from it the sound sits. Because it reads the repeat of the whole waveform, a string whose fundamental the microphone barely catches still reads at its true pitch.
The notes come from twelve-tone equal temperament: each octave doubles the frequency and is split into twelve equal semitones, each a ratio of 2 to the power 1/12, counted from a reference A. With A4 at 440 Hz every note has one frequency, which is why the tunings table can list them, and moving A4 moves all of them together.
The ideas behind the controls
- Fundamental
- The lowest frequency in a note and the rate at which the whole sound repeats. A guitar's low E is 82.41 Hz at A4 = 440 Hz.
- Harmonics
- The frequencies at two, three, four and more times the fundamental that sound with it. On a bass string they can carry most of what a small microphone picks up.
- Cent
- A hundredth of a semitone, 1,200 to the octave. Tuning is counted in cents because a cent is the same musical distance at every pitch.
- A4 reference
- The pitch the scale is built from, 440 Hz unless you set another. Moving it moves every note by the same number of cents.
- In tune
- On this tuner, within 3 cents of the note either side.
Online tuner FAQ
How do I tune a guitar with this online tuner?
Choose Guitar, standard, press Start tuner and allow the microphone. Play the low E string on its own and let it ring: the tuner names the string it is nearest to and shows how many cents off it is. Flat means tighten the string (tune up), sharp means loosen it (tune down). Turn the peg a little at a time until the reading says In tune, which is within 3 cents of the note, then do the A, D, G, B and high E strings the same way. Check all six once more at the end: changing one string's tension can move the others a little, most of all on a guitar with a floating tremolo.
What is A440?
A440 is the A above middle C (A4) tuned to 440 Hz, the reference pitch every other note is counted from. In equal temperament each semitone is a frequency ratio of 2 to the power 1/12, so A4 at 440 Hz puts middle C at 261.63 Hz and a guitar's low E at 82.41 Hz. ISO 16 sets 440 Hz as the standard tuning frequency, and it is the tuner's default. Not every ensemble tunes to it, so A4 can be set anywhere from 415 to 466 Hz here, and every note and string moves with it.
What is a cent in music?
A hundredth of an equal-tempered semitone. An octave is 1,200 cents, and one cent is a frequency ratio of 2 to the power 1/1200, about 0.06%. Cents measure tuning the same way at every pitch, which hertz cannot: 3 cents is 0.76 Hz at A4 (440 Hz) and 0.14 Hz at a guitar's low E (82.41 Hz). The tuner calls a note in tune within 3 cents either side.
Why does the reading jump around or stay blank?
The tuner shows a note only when the sound repeats cleanly, so it stays blank on silence, noise, talking or two strings ringing together, and it moves when the sound changes faster than the reading settles. To steady it, play one string at a time and mute the others with your hand, pluck with the soft part of your thumb, hold the phone or laptop close to the instrument, and read once the note has steadied, since a hard pluck starts a little sharp. If it stays blank, check that the right microphone is chosen and that its level is up in your system's sound settings. The line under Start also says when the browser kept its noise suppression on, which can turn a held note down.
How do I tune the low strings of a bass with a phone?
Choose Bass, 4-string or Bass, 5-string, and hold the phone close to the strings, or near the amplifier's speaker if the bass is plugged in. A phone microphone often picks up little of a low E's 41.20 Hz fundamental, or of a five-string's low B at 30.87 Hz, but the harmonics above it repeat at the same rate, and the tuner reads that rate, so the string still reads at its true pitch. Let it ring: under 100 Hz the tuner reads about the last 0.2 seconds of sound to stay within a fraction of a cent, so the reading takes a moment longer to settle than on a guitar's top strings. Keep the other open strings muted, since one ringing beside it can take over the reading.
Is a phone or laptop microphone accurate enough for tuning?
For pitch, yes. A tuner measures time: how long the waveform takes to repeat. A microphone's frequency response changes how loud each harmonic arrives, which leaves the time the wave takes to repeat as it was, and the device's sample clock would have to be off by about 0.06% to move a reading by one cent. In this site's tests the detector reads test tones from 27.5 Hz to 4.2 kHz within 0.2 cent of their true pitch. What limits a real reading is the sound that reaches the microphone: noise, other strings ringing and a note still settling after the pluck.
Can I tune to A4 = 432 Hz or 442 Hz?
Type the reference into the A4 field, or step it with the minus and plus buttons, anywhere from 415 to 466 Hz. Every note, every string and every reference tone moves with it, so at A4 = 432 Hz a guitar reads in tune with its low E at 80.91 Hz. The setting is remembered in this browser until you change it or press Back to 440 Hz.
What is a chromatic tuner?
A tuner that names the nearest of all twelve notes, so it works for any instrument and any tuning: a wind instrument, a voice, an open or dropped guitar tuning. Choose Chromatic (any note) in the instrument list and the tuner shows the note, its octave and how many cents off it you are. The instrument settings do the same arithmetic against one instrument's open strings, so they can name the string and say which way to turn its peg.
How do I tune a ukulele, violin, viola or cello?
Choose the instrument. A ukulele in standard tuning is G4, C4, E4, A4, with the G above middle C, and the low-G setting drops that string an octave to G3. A violin is G3, D4, A4, E5, a viola C3, G3, D4, A4 and a cello C2, G2, D3, A3. String players usually tune the A string first and the others from it. Bow or pluck each open string evenly, and on a violin, viola or cello use the fine tuners for the last few cents.
Does the tuner record or upload anything?
No. The sound is analyzed inside your browser as it arrives, and nothing is recorded, stored or sent. The page keeps only the instrument and the A4 reference you chose, in this browser's storage. Turn microphone off releases the microphone at once.