Pitch detector
Sing, hum or play a note: see its name, its frequency and how sharp or flat it is, live.
A pitch detector listens through your microphone and shows the note you sing or play, its frequency in hertz and how far it is from the exact note in cents (100 cents = one semitone). Standard tuning puts A4 at 440 Hz and middle C at 261.63 Hz. This one runs entirely in your browser: nothing is recorded.
About your microphone
- Why: to hear the note you sing or play and show its name and tuning.
- What happens: the sound is analysed live, in this browser, a few dozen times per second. Nothing is recorded, stored or sent, not even to us.
- You stay in control: a Stop button turns it off, and leaving or hiding the page turns it off too.
Your browser will ask for permission. Sing in a quiet room, about an arm's length from the phone or laptop. On iPhone, the page may sound quieter while the microphone is on; headphones help.
Waiting for your browser's permission prompt… (look near the address bar)
Microphone on, analysed on this device only
The microphone is blocked
No problem, and nothing was recorded. If you change your mind: open your browser's site settings for this page, allow the microphone, then reload.
No microphone found
This device has no microphone the browser can use. Plug in a headset or try on your phone.
The microphone is busy
Another app or tab is using it (a call, a recorder). Close it, then try again.
This browser can't use the microphone here
Microphone access needs a recent browser (Safari 14.3 or later on iPhone, or current Chrome, Edge or Firefox). In-app browsers (Instagram, TikTok, Facebook) often block it: open this page in Safari or Chrome.
Allow the microphone to start
Note frequencies (A4 = 440 Hz)
| Note | Octave 2 | Octave 3 | Octave 4 | Octave 5 |
|---|---|---|---|---|
| C | 65.41 | 130.81 | 261.63 | 523.25 |
| C♯ | 69.30 | 138.59 | 277.18 | 554.37 |
| D | 73.42 | 146.83 | 293.66 | 587.33 |
| D♯ | 77.78 | 155.56 | 311.13 | 622.25 |
| E | 82.41 | 164.81 | 329.63 | 659.26 |
| F | 87.31 | 174.61 | 349.23 | 698.46 |
| F♯ | 92.50 | 185.00 | 369.99 | 739.99 |
| G | 98.00 | 196.00 | 392.00 | 783.99 |
| G♯ | 103.83 | 207.65 | 415.30 | 830.61 |
| A | 110.00 | 220.00 | 440.00 | 880.00 |
| A♯ | 116.54 | 233.08 | 466.16 | 932.33 |
| B | 123.47 | 246.94 | 493.88 | 987.77 |
C4 is middle C. Each octave doubles the frequency; each semitone multiplies it by about 1.0595 (the twelfth root of 2).
How to get a stable reading
- One note at a time: the detector follows a single melody line, not chords.
- Hold the note steady and close to the microphone; a quiet room helps a lot.
- For low voices and bass strings, give it a moment: low notes need a longer wave to measure.
How it works
- Your browser reads 2,048 samples (about 43 ms) from the microphone, around 60 times per second. Voice processing (echo cancellation, noise suppression, auto gain) is turned off because it distorts pitch.
- The YIN algorithm finds the period of the wave; quiet frames and frames without a clear period are ignored, so it shows nothing rather than a wrong note.
- The frequency is matched to the nearest equal-tempered note at your reference (A4 = 440 Hz by default; set 442 if your ensemble tunes higher).
- Range: about 50 Hz to 2,000 Hz (G1 to B6), which covers voices and most melodic instruments.
Frequently asked questions
How does an online pitch detector work?
It reads short slices of sound from your microphone (about 43 milliseconds each), finds the repeating period of the wave with a pitch algorithm (here YIN), converts that period into a frequency in hertz, then names the nearest note and how far off it is in cents.
What do cents mean?
A cent is a hundredth of a semitone. 0 cents means exactly on the note; +20 means slightly sharp (high), −20 slightly flat (low). Most listeners don't notice errors below about 10 cents.
Can I use it to tune my guitar or violin?
Yes for a quick check: play one string at a time and bring the needle to 0. It detects one note at a time, so it can't read chords.
What frequency is middle C?
Middle C (C4) is 261.63 Hz in standard tuning, where A4 is 440 Hz. Each octave doubles the frequency: C5 is 523.25 Hz.
Why does it jump between octaves or show nothing?
Breathy, very quiet or very low notes have little clear pitch. Sing or play a steady tone, close to the microphone, in a quiet room. Chords and several voices at once can't be named as a single note.
Is the sound recorded?
No. The analysis happens in your browser; no audio is stored or sent anywhere.