Online bass tuner, free, with your mic

This is a free online bass tuner that listens through your microphone. It opens on four string bass, E A D G, and a five string preset with the low B is one click away in the menu. Press Start, play one open string, let the note settle, then aim for 0 cents. It is chromatic, so it names any note you give it, which is what you need for a dropped or lowered tuning. No account, no download. It sits alongside the rest of our free guitar tools.

Standard bass tuning: E A D G

A bass is tuned in fourths, like the bottom four strings of a guitar, one octave lower. From the thickest string to the thinnest: E, A, D, G. A five string bass adds a low B underneath, and leaves the four others exactly where they were.

Those numbers are the whole reason a bass is harder to tune than a guitar. A guitar's lowest string sits at 82.41 Hz; a four string bass starts at 41.20 Hz and a five string at 30.87 Hz. Lower means slower, and slower means the tuner needs more of the note before it can name it.

How to tune a bass guitar

Five steps, in this order. The whole point is to give the tuner one clean note at a time.

1. Press Start and allow the microphone. Nothing is recorded or uploaded: the signal is analyzed in your browser and discarded.
2. Play the open E string, the thickest one, with your usual attack rather than a hard one. Mute the other strings with your palm so only one note reaches the microphone.
3. Wait for the reading to settle, then look at the cents. Flat means too low, so tighten the string. Sharp means too high, so loosen it. Turn the tuning key slowly: a bass peg moves the pitch a long way for a small turn.
4. Do the same for A, D and G, and for the low B first if you play a five string.
5. Go back over all the strings once. Tightening one pulls slightly on the neck, so the first pass is never quite the last word.

Tuning a bass by ear

A bass has one real advantage over a guitar here, and it is worth knowing before you need it: every string tunes at the 5th fret, with no exception. On a guitar the B string breaks the pattern and you have to use the fourth fret. On a bass the gaps between strings are all the same, so one move covers the whole instrument.

1. Get one string right first. The E is the usual choice: take it from a piano, from a tuned instrument, or from the tuner above.
2. Press the fifth fret of the E string. That note is an A, the same note as the open A string next to it. Play them one after the other, then together, and turn the A string until they stop fighting each other.
3. Repeat the same move along the neck: fifth fret of A gives the open D, fifth fret of D gives the open G. That is the whole method.
4. On a five string, work the low B the other way round. The fifth fret of the B string should sound like the open E, so the string you already trust gives you the one you do not.
5. Finish with harmonics if you want to be fussy. The harmonic over the fifth fret of one string matches the harmonic over the seventh fret of the string below it, and harmonics beat against each other far more audibly than low fretted notes do.

Two notes nearly in tune do not sound like two notes. They sound like one note with a slow wobble in it, and that wobble slows down as the two pitches come together. That is what you are listening for, and it is easier to hear than high or low. The full ear method, including the guitar exception, is on how to tune a guitar.

Why low strings are harder to tune

This is physics, not a fault in your bass or in the tuner. The open E of a four string bass vibrates around 41 Hz. The low B of a five string sits near 31 Hz. Those are long, slow waves, and three things follow from that.

• A low note takes longer to measure. To recognize a pitch, the tuner needs several full cycles of the wave. At 31 Hz a cycle lasts about 32 thousandths of a second, close to three times longer than a guitar's low E. That is why the tuner lengthens its analysis window as soon as a bass preset is active: the reading arrives a moment later, and it is worth the wait.
• Small speakers and small microphones barely hear it. A phone microphone is designed for speech. It does hear a bass, but the fundamental is the weakest part of what reaches it, so a quiet room matters more here than anywhere else.
• Your ear is less sure down there. We hear pitch differences less precisely in the low register, which is why a bass can feel in tune on its own and sound off against a guitar.

If a low string refuses to settle, use its harmonic. Rest a finger lightly over the twelfth fret, directly above the metal, and play. You get the same note one octave higher, which the microphone and the detection both handle far more easily. Tune that harmonic, and the open string underneath is tuned with it.

Electric or acoustic bass: same tuner

One tuner for both. What changes is how you feed it sound, because an unplugged electric bass is a quiet instrument.

Tuning a ukulele next? There is a dedicated ukulele tuner page, and the guitar tuner page covers standard and alternate guitar tunings.

Who made this

Guitar Social Club is the work of Yohann Abbou, a guitar teacher in Paris. He teaches adults, which shapes everything here: people with jobs, limited practice time and a clear idea of the songs they want to play. The tools come out of his lessons, which is why none of them asks you to sign up before it works, and why this one shows you cents rather than a green light. The rest of our free guitar tools work the same way.

More about Yohann and how these tools are made.