Bass Tuner
A free bass tuner for 4-string and 5-string bass guitar: play an open string and the needle shows whether to tune up or down.
Your microphone is analysed on this device and is never recorded or sent.
Keyboard: Space starts and stops the tuner.
How to use the bass tuner
This online bass tuner listens for the deep fundamental of an open string. Press Start tuner, let the browser use the microphone, then play one string with a finger or a pick and let it sustain. Your microphone is analysed on this device and is never recorded or sent.
In Auto the bass tuner decides which string is sounding, from the low B of a five-string up to the G, and the message says whether to tighten or slacken that tuning key, with a semitone count when you are far off. The string buttons play a plucked bass tone and hold the tuner on that string. On a keyboard, 1 is the G string, 4 the E (and 5 the low B on a five-string), A returns to Auto and Space starts or stops. Switch between Standard (4-string), 5-string and Drop D in the Tuning menu. The needle is explained on the chromatic tuner page.
Standard bass tuning: E A D G
A 4-string bass is tuned like the double bass: the same letters as the four lowest guitar strings, one octave lower. String 1 is the thin G, string 4 the thick E.
| String | Note | Frequency at A4 = 440 Hz | An octave below |
|---|---|---|---|
| 4 | E1 | 41.20 Hz | Guitar string 6 (E2) |
| 3 | A1 | 55.00 Hz | Guitar string 5 (A2) |
| 2 | D2 | 73.42 Hz | Guitar string 4 (D3) |
| 1 | G2 | 98.00 Hz | Guitar string 3 (G3) |
Bass parts are written an octave higher than they sound, so the open E on your part is written E2 on the staff while the tuner, which names the sounding pitch, shows E1. Same string, same letter, one octave apart.
| Tuning | Notes, lowest string first | What changes |
|---|---|---|
| Standard (4-string) | E1 A1 D2 G2 | The usual four strings. |
| 5-string | B0 E1 A1 D2 G2 | Adds a low B string below the E, at 30.87 Hz. |
| Drop D | D1 A1 D2 G2 | String 4 down a whole step, from E to D; the three lowest open strings make a D power chord. |
Low notes and the microphone
The open E vibrates about 41 times a second and the low B about 31. The tuner listens down to about 26 Hz and waits for two full vibrations before it reads, so a low string takes a moment longer to show than a guitar string. Pluck firmly and evenly and keep the note ringing.
If the reading jumps around on the E or B string, play the 12th fret harmonic (touch the string lightly over the 12th fret wire and pluck). It sounds an octave higher, and the tuner shows the same letter one octave up. Through an amplifier, set the phone close to the speaker cone.
Check with harmonics
Harmonics give a bass player a quick check by ear. The harmonic at the 5th fret of one string is two octaves above that open string, and the harmonic at the 7th fret of the next string up is the same note: 5th fret on E and 7th fret on A both give an E, 5th on A and 7th on D give an A, 5th on D and 7th on G give a D. Play each pair together and turn the higher string until the wobble between them stops.
The two harmonics differ by about 2 cents in theory, because the 7th fret harmonic is a pure fifth and a fretted fifth is slightly narrower, so finish with the tuner.
Scale length and after tuning
The standard bass scale length is 34 inches (86 cm); short-scale basses run 30 to 32 inches and long-scale ones 35 inches. All of them are tuned to the same notes, so the same buttons and targets apply.
Once every string is green, go across once more, since changing one moves the neck a little. Then lock in with the metronome, learn shapes in the bass chord chart or run patterns from the bass scales page. Playing with a guitarist? Their guitar tuner uses the same A4 setting.
More for bass: Bass Chords · Bass Scales · Fretboard Notes · Guitar Tab Maker · Bass Amp Simulator · Online Looper
Questions
What are the notes of a bass guitar?
A 4-string bass is tuned E1 A1 D2 G2 from the thickest string to the thinnest. A 5-string bass adds B0 below the E.
Is bass tuned like a guitar?
The four bass strings have the same letters as the four lowest guitar strings (E A D G), one octave lower.
Why does the tuner struggle with my low B?
The low B is about 31 Hz, and the tuner needs a steady note that low. Let it ring, play the 12th fret harmonic, which is an octave higher, or move the microphone closer to the amplifier.
How do I tune a bass to drop D?
Choose Drop D in the Tuning list and lower string 4 from E1 to D1 until the needle is centered. The other strings stay the same.