Free · microphone · nothing uploaded
Tuner, for whatever you play.
The resident tunes nothing. He sits next to the guitar until it’s done.The microphone closes when you stop, when all is in tune, or after half a minute of quiet. Nothing is recorded.
–✓
Tap start, then play any note. A4 = 440 Hz.
Audio: your microphone, on only after you tap. The sound is analysed in this tab and never sent. Nothing about the audio reaches the visit count.
Tuner for any instrument, free and online: play one note into your phone’s microphone and I show its name, how many cents sharp or flat it is, and its frequency in Hz, against A4 = 440 Hz. It is a chromatic tuner, so it names all twelve notes, from B1 (61.7 Hz) to B6 (1976 Hz): guitar, bass, violin, a horn, your voice. Nothing to install.
For a stringed instrument, pick its page below: the guitar and ukulele tuners hear which string you play, the others ask for each string in turn, and every one says whether to tune up or down. Before you start the microphone, a tap on a string plays the note it should be. The guitar tuner listens for E A D G B E, low to high (E2 at 82.41 Hz to E4 at 329.63 Hz), with drop D, half step down, DADGAD, open G and open D a tap away. The ukulele tuner listens for G C E A (G4 C4 E4 A4, the G above the C), with low G, D tuning and baritone.
Daniel’s first band was called Timeless, the band of the Musikschule Obere Saar. Five guitarists. He and a friend were the worst two, playing power chords on one and three. They once played rock in a retirement home. The band got better when they left. Timelessly bad.
A tuner wouldn’t have saved them, but it saves a lot: in tune, even simple chords sound right.
I listen only after you tap Start tuning, and nothing is recorded.
Tuned up? Play something, or hum a line into the app and hear it become a track. About Daniel.
How to use a tuner
- Tap Start tuning and allow the microphone. Hold the phone near the instrument, in a quiet room. Play one note and let it ring: pluck once, firmly, and give it a moment, because the first instant of a pluck is brighter than the note.
- Read the note name first. If it shows the wrong letter, you are probably more than half a semitone off: turn until the right name appears. Then the needle and the cents: left of the middle is flat, right is sharp, and 100 cents make a semitone.
- Tune up to the note. If you are sharp, go a little below and come back up, so the string and the gear settle under tension and hold. The tick shows once you stay within five cents for about 0.4 seconds.
- Tune every string (on a guitar, low E to high E), then go round once more: each string you tighten pulls the neck a little, and the first ones move.
The switch under the tuner sets A4: 432, 440 or 442 Hz. Playing a trumpet, clarinet or saxophone? This page reads concert pitch; see below.
Themes
How to tune your instrument: the standard tunings
Know its notes first. These are the open strings as they sit on the neck, at A4 = 440 Hz. The guitar, bass, ukulele and banjo pages have the other tunings as switches.
| Instrument | Notes | Hz |
|---|---|---|
| Guitar | E2 A2 D3 G3 B3 E4 | 82.4 · 110.0 · 146.8 · 196.0 · 246.9 · 329.6 |
| Bass | E1 A1 D2 G2 | 41.2 · 55.0 · 73.4 · 98.0 |
| Ukulele | G4 C4 E4 A4 (the G is above the C) | 392.0 · 261.6 · 329.6 · 440.0 |
| Violin, mandolin | G3 D4 A4 E5 (on a mandolin, each a pair in unison) | 196.0 · 293.7 · 440.0 · 659.3 |
| Viola | C3 G3 D4 A4 | 130.8 · 196.0 · 293.7 · 440.0 |
| Cello | C2 G2 D3 A3 | 65.4 · 98.0 · 146.8 · 220.0 |
| Banjo, open G | G4 D3 G3 B3 D4 (the short fifth string first) | 392.0 · 146.8 · 196.0 · 246.9 · 293.7 |
What is a tuner?
A tuner is a device that hears a note and shows how far it is from the nearest correct pitch, so you can turn a peg, a slide or a mouthpiece until it matches. A chromatic tuner names any of the twelve notes; a guitar, bass, violin or ukulele mode only looks for that instrument’s strings, which is quicker for that instrument and no use for any other. This page is the chromatic one; the instrument pages listed above are the instrument modes.
On the instrument, the tuners are also the pegs or machine heads that tighten each string, so a “tuning device” can mean either. The word has other lives: the part of a radio or TV that picks a station, a person who tunes pianos, someone who modifies cars, or the modified car itself, and a film.
Clip-on tuner, pedal, phone or strobe
They all measure the same thing. They differ in what they listen to.
| Kind | Hears | Good for | Weak spot |
|---|---|---|---|
| Clip-on tuner | The vibration of the headstock, through the clamp | Acoustic guitar, ukulele, violin, banjo in a noisy room | Hears only what it is clipped to; needs a battery. About $13 to $35 in US shops (October 2026) |
| Pedal tuner | The signal in the cable | Electric guitar and bass on stage, tuning in silence | Needs a cable, so no acoustic instrument without a pickup |
| Phone or browser, like this page | The air, through the microphone | Any instrument, wind and voice included, nothing to buy | Hears the room too; this page reads from about 60 Hz up |
| Strobe tuner | A microphone or a cable, shown as a turning pattern | Setting intonation and workshop work, read to a tenth of a cent | Price and size |
| Tuning fork, pitch pipe | Nothing: it gives you one note | Tuning by ear, a choir’s starting note | You do the listening |
Most clip-ons read to ±1 cent, calibrate from 430 to 450 Hz and run on a CR2032 coin battery; many are a metronome too (here that is the metronome).
A clip-on is used like this page: clip it to the headstock (on a violin, the scroll), set it to chromatic or to your instrument, pluck, read. At home a phone does the job. For a gig, keep a clip-on in the case: in a loud room it is the one that hears only your instrument.
Cents, Hz and how close is in tune
Hz counts vibrations per second; A4 makes 440 of them. A cent is a hundredth of a semitone, the same step in every octave, which is why tuners show cents rather than Hz: 5 cents is 1.27 Hz at A4 but 0.24 Hz on a guitar’s low E.
Within 5 cents is in tune for most playing. Two A4s 5 cents apart (a violin’s A string) beat about 1.3 times a second, a slow swell rather than a sour note; on the low E it is one beat every four seconds. Closer than that rarely lasts: warm a steel string with your hands or the stage lights and it goes flat.
A4 = 440 Hz is the international standard, set in ISO 16 (1955, confirmed 1975). Many orchestras in Germany, Austria and Scandinavia tune to 442 or 443, 7.9 and 11.8 cents higher; 432 is 31.8 cents lower, about a third of a semitone (where 432 comes from). For an orchestra at 443, set the switch to 442 and tune about 4 cents sharp. The one that matters is the one the others in the room use.
Why the tuner jumps or shows the wrong note
- The attack. The first instant of a pluck or a bow stroke is full of overtones. Let the note settle before you read it.
- The wrong octave. An overtone can be louder than the note itself, so the letter is right and the octave isn’t. Pluck with the flesh of the thumb over the end of the neck, not with the nail near the bridge.
- Other strings ringing. Open strings sound along in sympathy. Rest a hand on the ones you are not tuning.
- Low notes. This page reads from about 60 Hz up, so a bass’s low E (41.2 Hz) and A (55 Hz) show as E2 and A2, an octave up; the cents are still right. The bass tuner reads them at their own octave.
- Noise. Talking, a fan or a second instrument mixes in. Get closer to the phone, or use a clip-on.
- Vibrato. A singer’s or a violinist’s vibrato swings the needle on purpose. Hold a straight tone to tune.
Concert pitch and transposing instruments
A chromatic tuner names the pitch that sounds, called concert pitch. Several wind instruments read music written higher than it sounds:
| Instrument | A written C sounds as |
|---|---|
| B♭ trumpet, B♭ clarinet, soprano saxophone | B♭, a whole tone lower |
| A clarinet | A, a minor third lower |
| Tenor saxophone | B♭, an octave and a whole tone lower |
| Alto saxophone | E♭, a major sixth lower |
| Baritone saxophone | E♭, an octave and a major sixth lower |
| French horn in F | F, a fifth lower |
So on this page a trumpeter’s written C shows as B♭, and nothing is wrong with the trumpet. The trumpet, clarinet and saxophone tuners do the transposing. Flute, oboe, trombone and the violin family sound as written; guitar and double bass an octave lower, which no tuner minds.
In tune, but chords still sound off
A tuner sets the open strings. Whether the fretted notes land is intonation, and that is set at the bridge. Check it on a guitar or bass: tune the open string, then fret the same string at the twelfth fret. It should read the same note an octave up, within a few cents. Sharp at the twelfth fret: the saddle moves back, away from the neck. Flat: forward. A screwdriver job on most electrics, a job for the shop on most acoustics.
New strings stretch. Tune, pull each one gently away from the fretboard along its length, tune again; steel strings settle within a day or two of playing, nylon strings (classical guitar, ukulele, harp) take several days to a week. A capo pulls strings sharp when it presses too hard or sits far from the fret. And some of it is the system: in equal temperament a major third is 13.7 cents wider than a pure one, on every instrument with frets or keys. Tune the B string a few cents flat for one chord and the others get worse.
How often to tune
Every time you pick the instrument up, and again once it has reached room temperature: out of a cold car or into a hot room, wood and strings go on moving for a while. Check again after hard playing, big bends or a change of tuning.
Tuning without a tuner
You need one reference note and your ears. Take it from a tuning fork, a piano, the tone generator, or any instrument page here, where a tap on a string plays its note before you start the microphone (on a phone speaker, notes below A2 an octave up). Play your string against it. Out of tune, the two wobble against each other; turn until the wobble slows down and stops.
A guitar can tune itself against its low E. The fifth fret of each string gives the next open string (E to A, A to D, D to G, B to E), except the G string, where the fourth fret gives the B. If the low E was off, the whole guitar is off with it, but in tune with itself.
The best free tuner app: what to look for
It reads fast and holds still, shows cents rather than only a light, has a chromatic mode for anything, and lets you change A4. For your instrument it knows the tunings and spells them the way players do: the guitar tuner writes half step down as E♭ A♭ D♭ G♭ B♭ E♭. This chromatic page writes C♯ and F♯, and E♭, A♭ and B♭. All of it runs in the browser, without an install, an account or ads. What it can’t do is ignore a loud room; that is what a clip-on is for.
The hardest instrument to play, and to tune
The ones usually named are the French horn (its notes sit close together high in its range), the violin (no frets), the oboe (the reed) and the bagpipes (breath and bag at once); for tuning, the piano wins: a piano has around 230 strings for its 88 keys, and its octaves are tuned slightly wide on purpose, so a chromatic tuner calls a well-tuned piano sharp at the top and flat at the bottom: that is a technician’s job, with a tuning hammer. A concert pedal harp has 47 strings, a 12-string guitar six pairs with the low four in octaves, a sitar eleven to thirteen sympathetic strings under its playing ones. The violin and the trombone are tuned in a minute; the hard part there is playing in tune.
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