About the Online Tuner
A tuner tells you whether a note is too high, too low or just right. This one listens through your microphone, works out the pitch of the sound in real time and shows the name of the nearest note, the exact frequency in hertz and how many cents you are away from perfect. A needle moves left for flat and right for sharp and the circle turns green when you are within five cents. It also tells you the closest guitar string. It is a chromatic tuner, so it works for guitars, ukuleles, violins, pianos, voices and any other instrument that plays one note at a time. The sound is analysed in your browser and is never recorded or sent anywhere.
Updated October 2026
How to use the Online Tuner
- 1Press Start tuner and allow the microphone.
- 2Play a single note on your instrument, one string at a time.
- 3Read the note name and the needle.
- 4Tighten the string if the needle says flat, loosen it if it says sharp.
- 5Stop when the circle turns green.
Tuning a guitar step by step
Start with the thickest string and pluck it gently. If the needle is to the left, the string is flat, so tighten it a little. If the needle is to the right, it is sharp, so loosen it. Always come up to the note from below, which keeps the string stable, and then check it again after you have tuned the other strings, because the neck changes slightly.
New strings stretch for the first days, so re-tune often at the start. Tune in a quiet place and keep your phone near the sound hole, not touching the guitar.
Other instruments
- Ukulele: G4, C4, E4, A4.
- Violin: G3, D4, A4, E5.
- Bass guitar: E1, A1, D2, G2.
- Banjo (open G): G4, D3, G3, B3, D4.
- Piano: tune to A4 first, then use the notes either side of it.
- Voice: sing a long note on one vowel and read the average.
Related tools
Listen to a reference pitch with the Tone Generator, keep steady time with the Online Metronome, and test your microphone with the Mic Test before you start. The Audio Equalizer lets you shape the sound of a recording. The tuner works best in a quiet room, so close the window and turn off the fan.
Features
- Chromatic: every note
- Frequency in Hz and offset in cents
- Needle meter and green in-tune circle
- Closest guitar string shown
- Choice of A4 reference: 415, 432, 440, 442, 444
- Microphone sound stays in your browser
- Works on phones and computers
Frequently asked questions
How does the tuner hear the pitch?
It looks for the repeating pattern in the sound wave using autocorrelation. The time between repeats gives the frequency, from which the note name and cents are worked out.
What does cents mean?
A cent is one hundredth of a semitone. Five cents sharp or flat is hard to hear, so within five cents counts as in tune.
What are the standard guitar notes?
From the thickest string to the thinnest: E2, A2, D3, G3, B3 and E4, at about 82, 110, 147, 196, 247 and 330 hertz.
Why doesn't it detect my note?
It needs a clear, fairly loud, single note. Move closer to the microphone, play one string at a time, and avoid background noise. Very low or very quiet notes are harder to detect.
What is A4 = 440?
It is the standard reference pitch for the note A above middle C. Some orchestras use 442 and some early-music groups use 415 or lower. Pick the one you need.
Is my sound recorded?
No. The audio is analysed live in your browser and then thrown away. Nothing is saved or uploaded.
Can I tune a voice?
Yes. Hold a steady note and the tuner shows the nearest note and how close you are. Voices wobble more than strings, so look at the average.