This online bass tuner listens to your bass through the microphone, recognizes which string you played and shows how many cents you are from the note. It covers 4-string bass (E A D G), 5-string (with the low B) and 6-string (with the high C), plus drop D and half step down.
The detector is set up for very low notes: it reaches down to about 25 Hz, below the low B of a five-string. Everything is processed in your browser and no sound is sent anywhere.
How to use it
- Tap Turn on microphone and allow access.
- Choose the tuning: 4-string, 5-string, 6-string, drop D or half step down.
- Pluck an open string firmly with your finger and let it ring. Its button lights up and the needle shows how far off it is.
- Up arrow (↑): tighten the tuning key. Down arrow (↓): loosen it. After a second in the green, the string gets a ✓.
- To hear the reference note, tap the string's button; that also locks the tuner onto it. Auto unlocks it.
Notes of 4, 5 and 6-string bass
A 4-string bass has the same notes as the four lowest guitar strings, one octave lower: E A D G (E1 A1 D2 G2; 41.2, 55, 73.4 and 98 Hz). A 5-string adds a low B (B0, 30.9 Hz), a staple in gospel, worship and modern pop bands. A 6-string also adds a high C (C3, 130.8 Hz) on top.
Why phones struggle with the low B
Phone microphones pick up very little below 50 Hz, so the fundamental of the low B almost disappears and mostly its overtones come through. The tuner corrects the octave on its own, but it helps to play close to the mic, with your finger instead of a pick, or to use the 12th-fret harmonic, which is the same note an octave higher.
Tips
- Pluck with the pad of your finger and mute the other strings: a clean tone reads faster.
- With an active bass plugged into an interface, switch off effects and keep the bass volume up.
- Tune up to the note; a thick string that overshoots and comes back down tends to slip later.
- New bass strings stretch a lot: check again after a few minutes of playing.
Frequently asked questions
What are the notes of a 4-string bass?
From the 4th string (the thickest) to the 1st: E, A, D and G, the same as the four lowest guitar strings, one octave lower.
How do I tune a 5-string bass with a low B?
Choose 5-string (low B) and tune B, E, A, D and G. The low B sits a fourth below the E. There's also a 5-string option with a high C (E A D G C) in the menu.
Why can't my phone pick up the low E or B string?
The low B is about 31 Hz and the low E about 41 Hz, frequencies phone mics barely capture. Pluck harder and closer to the mic, use the 12th-fret harmonic, or plug the bass into an audio interface.
How do I tune a bass to drop D?
Choose Drop D and lower the 4th string from E to D, a whole step. The rest stay the same: D A D G.
Can I use a guitar tuner to tune a bass?
Usually, yes: the bass strings have the same names as the four lowest guitar strings, an octave lower, and a chromatic tuner reads any note. This page goes further: it's set up for low frequencies, knows the bass tunings and detects which string you're playing.
Is a bass tuned an octave lower than a guitar?
Yes. The four strings of a standard bass are E A D G, exactly one octave below the four lowest strings of a guitar. An upright (double) bass uses the same notes, so this tuner works for it too.
How often should I tune my bass?
Every time you pick it up, and again after changing strings or moving between rooms with different temperatures. It takes less than a minute.
How do I tune a bass half a step down?
Choose Half step down: every string drops a half step to E♭ A♭ D♭ G♭, which the tuner shows as D♯ G♯ C♯ F♯.