Loading tool…
Pluck a string and see at a glance whether it is flat, sharp or spot on. The tuner listens through your microphone, shows the note and how many cents away it is, and can play the target pitch for each string so you can tune by ear as well.
Processing locally on your device
Overview
Pitch detection is the heart of a tuner. This one uses the YIN algorithm, a time-domain method that looks for the delay at which the waveform best repeats itself. For each block of 4,096 microphone samples it computes a difference function, normalises it so the true period stands out from its multiples, and refines the best dip with parabolic interpolation for sub-sample precision. YIN copes far better with real instruments than picking the loudest peak of a spectrum, because the fundamental of a low guitar or bass string is often weaker than its second or third harmonic.
Once the frequency is known, the tuner finds the nearest note in equal temperament and the offset in cents, where 100 cents make one semitone: cents = 1200 × log₂(measured ÷ target). A reading within ±5 cents turns the needle green, and most players aim for ±2–3 cents on a sustained note. Readings are taken about 25 times a second and smoothed with a short median filter, which steadies the needle without making it sluggish when you move to the next string.
Low notes are the hardest. The low E of a guitar at 82.41 Hz repeats every 12 ms and the low E of a bass at 41.2 Hz every 24 ms, so the analysis window has to hold several cycles; at 48 kHz, a 4,096-sample block covers about 85 ms. The detector works from about 30 Hz to 1.6 kHz, which covers bass, guitar, ukulele, violin and voice. Echo cancellation, noise suppression and automatic gain are turned off for the microphone, because those phone-call features can distort the waveform a tuner relies on.
The reference pitch is adjustable from 430 to 450 Hz. A4 = 440 Hz is the modern standard, many orchestras tune to 442 or 443 Hz, and some bands tune to match a recording or a fixed instrument such as a piano. Presets for standard and drop D guitar, four-string bass, ukulele (GCEA) and violin show each string’s target frequency; the tuner highlights the string closest to what you play and measures against it. Tap any string to hear its reference tone.
| Instrument | Strings (low → high) | Frequencies (Hz) |
|---|---|---|
| Guitar, standard | E2 A2 D3 G3 B3 E4 | 82.4 · 110 · 146.8 · 196 · 246.9 · 329.6 |
| Guitar, drop D | D2 A2 D3 G3 B3 E4 | 73.4 · 110 · 146.8 · 196 · 246.9 · 329.6 |
| Bass, 4-string | E1 A1 D2 G2 | 41.2 · 55 · 73.4 · 98 |
| Ukulele, GCEA | G4 C4 E4 A4 | 392 · 261.6 · 329.6 · 440 |
| Violin | G3 D4 A4 E5 | 196 · 293.7 · 440 · 659.3 |
Press Start tuner and allow microphone access when your browser asks.
Choose Chromatic or an instrument preset such as Guitar (standard) or Ukulele.
Set the A4 reference if your band or orchestra does not use 440 Hz.
Play one string or note and let it ring; tune until the needle sits in the green zone.
Tap a string button to hear its reference pitch if you want to tune by ear.
Use cases
Tune six strings in standard or drop D without hunting for a clip-on tuner. The tuner picks the string you are playing, so you can go from low E to high E without changing settings.
The bass preset handles the low 41 Hz E string, and the ukulele preset uses the re-entrant GCEA tuning with its high G4.
Set A4 to 442 or 443 Hz to match the rest of the group, then tune violin strings against the same reference.
In chromatic mode, sing a note and watch how many cents you sit above or below it, a simple way to practise holding pitch.
Pro tips
Answers to common questions about the online tuner.
It has to hear your instrument. The audio is analysed in your browser a few dozen times per second and immediately discarded; nothing is recorded, stored or uploaded. You can stop the microphone at any time with Stop tuner.
A cent is one hundredth of a semitone. A string that reads +20 cents is a fifth of a semitone sharp. Most people cannot hear a difference of less than about 5 cents on a single note, which is why that range is marked as in tune.
440 Hz is the standard for almost all modern music and is the default. Change it only to match a group or a fixed instrument tuned differently, for example 442 Hz for many European orchestras.
Yes. Choose Guitar (drop D) and the lowest string’s target becomes D2 at 73.42 Hz instead of E2, while the other five strings stay at standard pitch.
Background noise and other instruments mix with your note and make the waveform less periodic. The tuner ignores readings it is not confident about, so in a loud room move closer to the microphone or use a headset mic.
No. ToolEnhancer processes files on your own device inside the browser. They are never sent to, stored on or seen by our servers.
Yes. The online tuner is free to use with no sign-up, no watermarks and no daily limits.