Guitar Tuner
The low E string (E2) is 82.41 Hz when A4 is 440 Hz. Pluck a string and the needle shows how many cents sharp or flat it is, then turn the tuning peg until the needle sits in the middle.
How to use
- Choose Guitar, Ukulele or Bass, press Start tuning and allow microphone access. Nothing is requested until you press the button.
- Pluck one string and let it ring. In Auto mode the tool picks the closest string; the needle shows how far off you are. Turn the tuning peg until the needle sits in the middle and the tool says In tune.
- To tune one string by ear, tap it to lock it as the target and press Play tone for a reference note. Change the A4 reference (default 440 Hz) if your group tunes differently.
How it works
Each target note follows equal temperament: frequency = A4 x 2^((n - 69) / 12), where n is the MIDI note number and A4 is note 69. With A4 = 440 Hz, E2 is 82.41 Hz.
The pitch of your string is found with the YIN algorithm on the latest 0.1 seconds or so of microphone signal. The readout is the median of the last five detections to keep it steady.
The needle shows the distance to the target in cents: cents = 1200 x log2(detected frequency / target frequency). One semitone is 100 cents, and the tool calls a string in tune within 5 cents.
Open string frequencies
Standard tuning at A4 = 440 Hz, from the lowest string to the highest, calculated with equal temperament.
| Instrument | Strings | Frequencies (Hz) |
|---|---|---|
| Guitar | E2 A2 D3 G3 B3 E4 | 82.41, 110.00, 146.83, 196.00, 246.94, 329.63 |
| Ukulele | G4 C4 E4 A4 | 392.00, 261.63, 329.63, 440.00 |
| Bass | E1 A1 D2 G2 | 41.20, 55.00, 73.42, 98.00 |
FAQ
Why does the tuner jump around or show nothing?
Pluck one string at a time, let it ring and keep the room quiet. Other instruments and background noise confuse a single-note detector. Strumming a chord cannot be read. Hold the device close to the guitar.
Why is a ukulele G higher than C?
Standard ukulele tuning G C E A is re-entrant: the G string is tuned to G4, above the C string, which is C4. The tool lists strings in that order.
Does it work for bass?
Yes. Low notes such as E1 (41.20 Hz) need more signal to be heard, so pluck firmly and give the note a moment to settle. Phone microphones are weak at very low frequencies.
Is my audio recorded?
No. The signal is analyzed in your browser and is never stored or sent anywhere.