An online tuner for guitar, bass, ukulele and violin
This online tuner listens through your microphone and shows the note you play, its frequency in Hz and how many cents it is above or below the target. Pick your instrument and the tuner compares each note with the nearest string of the standard tuning, so you see at once which string you play and whether to tune it up or down. In chromatic mode it shows the nearest note of all twelve, for any instrument or your voice. No microphone? Press a string to hear its reference tone and tune by ear.
Standard tunings
The string list shows these notes and frequencies, calculated with A4 at 440 Hz. If you change the reference pitch, every frequency follows it.
| Instrument | Strings, low to high | Frequencies (Hz) |
|---|---|---|
| Guitar | E2 A2 D3 G3 B3 E4 | 82.41, 110.00, 146.83, 196.00, 246.94, 329.63 |
| Bass | E1 A1 D2 G2 | 41.20, 55.00, 73.42, 98.00 |
| Ukulele | G4 C4 E4 A4 | 392.00, 261.63, 329.63, 440.00 |
| Violin | G3 D4 A4 E5 | 196.00, 293.66, 440.00, 659.26 |
The ukulele row is in string order from string 4 to string 1: its G string is tuned to G4, higher than the C4 and E4 strings next to it. The tunings come from these sources: the guitar from an acoustics study by Dan Russell of Kettering University, the bass from a University of Illinois physics report, the ukulele from the Grinnell College Musical Instrument Collection and the violin from a Bucknell University acoustics course.
How the tuner finds the pitch
Your browser hands the tuner the microphone signal in short pieces of about a tenth of a second. A noise gate first checks that the piece is loud enough, so room noise does not move the needle. The tuner then looks for the time after which the waveform repeats itself, with the YIN method published by de Cheveigné and Kawahara in the Journal of the Acoustical Society of America in 2002. One divided by that time is the frequency. A short running median of the last readings keeps the needle steady.
Notes follow twelve-tone equal temperament, where each semitone is the twelfth root of 2 apart and an octave doubles the frequency, as described in the UNSW music acoustics notes. The reference A4 of 440 Hz is the standard tuning frequency set by ISO 16.
How to tune your instrument
- 1Choose Guitar, Bass, Ukulele, Violin or Chromatic, then press Start tuner and allow the microphone.
- 2Pluck or bow one open string and let it ring. The tuner shows the note, the string and the cents.
- 3If the needle is left of center the string is flat: tighten it. Right of center it is sharp: loosen it. Stop when the note turns green, then go to the next string.
Turn the peg slowly and watch the needle: a tighter string sounds higher, as the UNSW violin acoustics introduction explains. Keep a steady beat for practice with the metronome, or play any exact pitch with the tone generator.
Frequently asked questions
Is my microphone recorded or sent anywhere?
No. Your browser reads the sound from the microphone in short pieces, finds the pitch on your device and throws the sound away right after. Nothing is recorded, saved or uploaded. The tuner only listens after you press Start tuner, and Stop releases the microphone.
Which notes is a guitar tuned to?
In standard tuning the six strings from the thickest to the thinnest are E2, A2, D3, G3, B3 and E4. With A4 at 440 Hz these are 82.41, 110.00, 146.83, 196.00, 246.94 and 329.63 Hz. Pick Guitar above and the tuner shows which string you are playing.
What does the cents number mean?
A cent is one hundredth of a semitone. Minus means the string sounds too low (flat) and you tighten it to raise the pitch; plus means it sounds too high (sharp) and you loosen it. The tuner marks the note green when it is within 5 cents of the target.
Why does the tuner jump between notes or show nothing?
It needs one clear note at a time. Pluck a single string, let the other strings stop ringing and hold the instrument close to the microphone. Background noise, a very soft note or a chord makes the pitch unclear, and the tuner then waits instead of guessing. If a low bass string shows nothing, play it a little louder.
Should I set A4 to 440 Hz or something else?
Leave it at 440 Hz unless you play with others who tune differently. ISO 16 sets 440 Hz as the standard tuning frequency for this A, the A4 in the treble stave. If your group tunes to another A, set the same A4 here and every note follows it.
Can I tune without a microphone?
Yes. Press a string in the list to hear its reference tone, then tune that string by ear until both sound the same. This works on a phone or computer without giving microphone access.