Guitar and Bass Tuner — Microphone Pitch Detection

Online tuner for guitar and bass guitar with real-time microphone pitch detection. Six guitar tunings — Standard E, Drop D, Open G, Open D, DADGAD and ½ step down — and thirteen bass tunings for four, five and six strings, with the low B and A, tenor and piccolo. Adjustable A4 reference (415–466 Hz) and a reference tone for each string.

How to tune

4 steps
1
Allow microphone

Choose guitar or bass guitar and click "Start microphone" — the browser will ask for permission once.

2
Pluck a string

Pluck one string at a time, let it ring. The big note shows what was detected, the needle moves left of center if too low, right if too high.

3
Adjust the peg

Turn the tuning peg toward the green zone. When the needle sits in the green zone (±5 cents), the string is in tune.

4
Repeat for every string

The bottom row shows the strings of the current tuning, numbered as on the instrument: the highest number (6 on a guitar, 4 on a bass) is the thickest string, 1 the thinnest. A string lights up green when it is in tune.

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Tune your guitar or bass with the real microphone, right in the browser

Microphone off
—
Pluck a string
−50¢ target +50¢
Target — — Hz
Your browser will ask for microphone permission — needed for pitch detection
6 is the thickest string, 1 the thinnest
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Features

Real microphone detection
Pitch is read from the period of the signal (NSDF) in real time via the Web Audio API. No samples needed — just your microphone and your browser.
Guitar and bass guitar
Six guitar tunings and thirteen bass tunings: standard, Drop D, D and C standard, Drop C, BEAD, 5 strings with Drop A or high C, 6 strings, tenor and piccolo.
The five-string low B
For bass the tuner listens down to 19 Hz with a 170 ms window — a third below the lowest string. An octave jump inside one pluck is not believed: a peg never moves a string by an octave.
Auto-detect or locked string
Auto-detect recognizes a string that is less than a semitone out, and recognizes a 12th-fret harmonic. A locked string is guided to its note — and if a different string is sounding, the tuner says so instead of telling you to tighten.
A4 reference 415–466 Hz
Adjust the reference frequency for baroque (415), classical (442), or modern band tunings. All string targets shift accordingly.
Reference tone per string
The Ref button plays a plucked tone with overtones up to 2 kHz — audible through a phone speaker, which reproduces neither the 82 Hz of the guitar's low E nor the 31 Hz of the bass's low B.

FAQ

Does it work without a microphone?

No — pitch detection needs to hear the string. If you can't use a microphone, click the "Ref" button on any string to play its note and tune by ear.

How fine is the needle — will it hear a single cent?

Detection accuracy is around ±1 cent on a clean signal in a quiet room. The needle smoothing adds a small delay (~150 ms) for stability — that's why fast vibrato won't flicker the display.

Why does the wrong note show sometimes?

Background noise (TV, AC, traffic) can confuse pitch detection. Move closer to the microphone, turn off noisy appliances, and pluck strings cleanly without touching others.

How do I tune a bass with a phone when the tuner does not see the low E or B?

A phone microphone barely picks up anything below 60 Hz: of the low E (41 Hz) and B (31 Hz) it mostly hears the overtones. Tap the string's card to lock it and play the 12th-fret harmonic — it sounds an octave up, and the tuner folds it onto the string's note with the same accuracy in cents. Hold the phone close to the body near the neck.

Why did a low bass string show a note an octave higher?

As a low string fades, its fundamental and odd overtones die first, and the signal really does sound an octave up. Within one pluck the tuner does not believe such a jump and stays on the string's note. If the octave shows right after the pluck, lock the string — then the octave is folded onto its note.

What is A4 reference?

A4 = 440 Hz is the modern concert standard. Some orchestras use 442 or 443, baroque ensembles use 415 (half step down), and rock bands sometimes tune to 432. Change A4 and all target frequencies shift by the same ratio.

Auto-detect or locked string — which to use?

For routine tuning auto-detect is enough: it recognizes a string that is less than a semitone out. Further out (new strings, another tuning) it asks you to tap the string card — then it locks onto that string and guides it to its note. If a different string sounds while one is locked, the tuner offers to switch instead of telling you to tighten.

Can I tune a 7- or 12-string guitar?

Guitar tunings are six-string, bass tunings are for 4, 5 and 6 strings. The big note at the top always shows the note that is sounding, so you can tune the seventh string (B1) or the octave strings of a 12-string by it. Do not lock another string's card for them — its instructions are made for its own note.

Where is the chord library and strumming?

They live in the sibling tool — click "Guitar" in the top nav to open the full Acoustic Guitar with chord library, strum patterns, and recording.

💡 Want us to improve this tool just for you?

We can! Just send us a quick message with your idea. If you'd like to discuss it in detail, leave your email and we'll get back to you. You can stay anonymous.

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Who is this tool for?
🎵 Musicians & Producers
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