Bass Tuner
Tune your bass guitar two ways: let the microphone read each string with a live needle and cents readout, or tune by ear with clean reference tones. 4-string EADG, 5-string, Drop D and half-step down — free, in your browser.
Tuning
Strings
Tap a string to hear its reference tone — no microphone needed.
Microphone tuner
Your microphone is analysed on your device only — nothing is uploaded, saved or recorded.
How the Bass Tuner works
This online bass tuner works two ways. Press Start microphone, pluck a string, and it detects the pitch on your device, showing the nearest note in big type with a needle that swings toward sharp or flat; centre the needle and the note turns green when you are within a few cents. Because bass strings sit very low — the open E is only about 41 Hz — let each note ring cleanly for a steady reading, or tune by ear by tapping a string button to play its reference tone. Choose 4-string EADG, 5-string BEADG, Drop D or half-step down and the target strings update for both methods. Everything runs client-side with the Web Audio API, so nothing is installed and your microphone audio is never uploaded or recorded. Also play guitar? Try the Guitar Tuner, lock in your groove with the Metronome, or explore more Music Tools.
Open string frequencies
A 4-string bass in standard tuning sounds these open-string pitches — a full octave below the bottom four strings of a guitar. All frequencies are equal temperament referenced to A4 = 440 Hz.
| String | Note | Frequency | MIDI |
|---|---|---|---|
| 4th (low E) | E1 | 41.20 Hz | 28 |
| 3rd | A1 | 55.00 Hz | 33 |
| 2nd | D2 | 73.42 Hz | 38 |
| 1st (G) | G2 | 98.00 Hz | 43 |
At 41.20 Hz the open low E sits near the bottom of human pitch hearing, which is why bass strings need a longer, steadier note for any tuner to lock on.
Alternate tunings this tuner supports
| Tuning | Strings (as tuned) | Lowest pitch |
|---|---|---|
| 5-string (BEADG) | B0 E1 A1 D2 G2 | 30.87 Hz |
| Drop D | D1 A1 D2 G2 | 36.71 Hz |
| Half-step down | E♭1 A♭1 D♭2 G♭2 | 38.89 Hz |
Why does my low B or low E read unstable?
Because those notes are extremely low. A 5-string low B sits at about 30.87 Hz and a standard low E at 41.20 Hz, which means a single cycle of the waveform takes roughly 32 and 24 milliseconds. A tuner needs several complete cycles before it can state a pitch confidently, so the reading settles more slowly than it does on a guitar. Pluck firmly near the neck, let the note ring, and read the needle after it steadies rather than during the first moment of attack.
Frequently Asked Questions
How do I tune my bass with the microphone?
Pick a tuning (4-string EADG is the default), press Start microphone and allow your browser to use the mic, then pluck one string at a time. The tuner finds the pitch, shows the nearest note in large type, and swings a needle left or right. Turn the tuning peg until the needle sits at the centre and the note turns green — that means you are within a few cents of being in tune. Bass strings are very low, so let each note ring cleanly for the most stable reading.
What is standard bass tuning?
A standard 4-string bass is tuned E1, A1, D2, G2 — the same notes as the bottom four strings of a guitar but an octave lower. A 5-string bass usually adds a low B0 below that, giving B E A D G, while a 6-string adds a high C above. This tuner includes 4-string EADG, 5-string BEADG, Drop D and half-step down.
Can I tune my bass without a microphone?
Yes — you can tune a bass by ear. Tap any string button to hear that exact pitch — for example the low E string at about 41 Hz — and match your string to the tone by ear. This needs no microphone and no permission, so it works on any device, and it is handy in noisy rooms or for very low strings where microphone detection can be tricky.
Is my microphone audio uploaded or recorded?
No — the bass tuner analyses the microphone stream live on your device with the Web Audio API and never uploads, saves or records it. Everything happens inside the page, so no audio and no tuning data leaves your browser. Pressing Stop, or closing the tab, releases the microphone immediately, and the browser shows its own recording indicator the whole time the tuner is listening so you can always see when the mic is live.
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