Bass Tuner: Tune Your Bass Guitar Online
A free online bass tuner for 4-string and 5-string bass guitars. Tap Start, allow the microphone and play a string, down to the low B.
Ready
Tap Start, then play a string.
Settings
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How to tune a bass with the tuner
- Step 1Tap Start listeningYour browser asks to use the microphone. Choose Allow. For a 5-string bass or Drop D, pick it under Settings first.
- Step 2Play one open stringPluck firmly and let it ring. Auto finds the string, or tap a string to lock the tuner to it.
- Step 3Turn the tuning key until the needle is greenLeft of center is flat, so tune up. Right of center is sharp, so tune down. When every lamp is lit, the bass is in tune.
Bass guitar strings: E A D G
A 4-string bass is tuned E A D G, from the thickest string to the thinnest. That is one octave below the four lowest guitar strings: E1, A1, D2, G2. String 1 is the thin G, and string 4 is the low E at 41.20 Hz. The table adds the low B of a 5-string bass, at A4 = 440 Hz.
| String | Note | Frequency | On a 4-string |
|---|---|---|---|
| 1 | G2 | 98.00 Hz | Yes |
| 2 | D2 | 73.42 Hz | Yes |
| 3 | A1 | 55.00 Hz | Yes |
| 4 | E1 | 41.20 Hz | Yes |
| 5 | B0 | 30.87 Hz | No, 5-string only |
5-string bass: B E A D G
A 5-string bass adds a low B below the E, so it is tuned B E A D G. The B is B0, at 30.87 Hz, one of the lowest notes most people ever tune. Open Settings, choose 5 strings, low B, and a fifth string key appears. Tune the E first: it is easier to hear, and you can then check the B against the E at fret 5.
Why phones hear low strings poorly
Phone and laptop microphones are small, and they pick up very low notes weakly. At 41.20 Hz the low E is mostly heard through its overtones. The tuner reads the pitch from those, but a soft or short note can give no reading. To help it:
- Hold the phone close to the amp's speaker, or against the body of an unplugged bass.
- Pluck firmly over the pickups and let the string ring.
- Tap the string to lock it, then play the harmonic at the 12th fret. It sounds one octave higher and is easier to hear. The tuner reads it as the open string and says "octave up".
- On a computer, plug the bass into an audio interface and make it the default input.
Drop D on bass
Drop D lowers only the E string, a whole step down to D1 (36.71 Hz), so the bass reads D A D G. It gives you a low D without a fifth string. Choose Drop D, 4 strings, under Settings. Tune the low string down past D and come back up to it, so it holds. Expect the looser string to feel a little floppy. Your tuning stays in this browser, apart from the guitar tuner's settings.
Is my audio recorded?
No. Your browser analyzes the sound on your device and then discards it. Nothing is recorded, uploaded or stored, and the microphone turns off when you tap Stop or leave the page. Only your tuning and A4 reference are saved, in this browser. The privacy policy has the details.
FAQ
What are the notes of a bass guitar?
On a 4-string bass, E A D G from the thickest string to the thinnest: E1, A1, D2, G2. A 5-string adds a low B (B0) below the E.
Why does the tuner not pick up my low E or B?
A phone microphone hears very low notes weakly. Hold the phone close to the amp's speaker or the bass body, pluck a little harder, or tap the string and play its 12th fret harmonic, which the tuner reads as the open string.
Can I tune an electric bass without an amp?
Yes. An unplugged electric bass is quiet, so put the phone right next to the strings, near the pickups, and keep the room quiet. The harmonic at the 12th fret is often easier for the microphone to hear.
Is a bass tuned like a guitar?
The four bass strings have the same names as the four lowest guitar strings, E A D G, but sound one octave lower. A guitar tuner set to guitar will not reach them, so use the bass setting.
How close is in tune?
The needle turns green within 5 cents of the note. A string counts as tuned when it stays green for about a second, and its lamp lights.
Related tools
All audio toolsTune a 6-string guitar in standard, Drop D or an open tuning.
Find any note you play, in Hz and cents.
Check that your speakers or headphones play the low bass notes.
Maintained by NabeelUpdated Oct 20, 2026.