How to use
- Bass – 4-string (E A D G) is selected; for a 5-string choose Bass – 5-string (B E A D G).
- Click Start tuning and allow the browser to use the microphone.
- Pluck an open string firmly and let it ring for a few seconds. Tighten if the needle is left of centre, loosen if it is right, until it turns green.
- When every string is done, check them all once more.
Options explained
- Cents (¢)
- A semitone is 100 cents. Within ±5 cents is shown as in tune.
- Reference A4
- 440 Hz by default. The bass A string (A1, 55 Hz) is two octaves below it.
- Chromatic mode
- Shows the nearest note for any sound — use it for harmonics, Drop D or other tunings.
Target notes for 4- and 5-string bass
| String | Note | Frequency (Hz) | 12th-fret harmonic |
|---|---|---|---|
| 5 (5-string only) | B0 | 30.87 | B1 61.74 |
| 4 | E1 | 41.20 | E2 82.41 |
| 3 | A1 | 55.00 | A2 110.00 |
| 2 | D2 | 73.42 | D3 146.83 |
| 1 | G2 | 98.00 | G3 196.00 |
A bass is tuned exactly one octave below the four lowest strings of a guitar, so when both are in tune the open bass strings share note names with guitar strings 6, 5, 4 and 3.
When the microphone struggles
- Use the amp. An unplugged electric bass is very quiet. Plug in, set the volume to your normal practice level and put the phone in front of the speaker.
- Tune the harmonic. Touch the string lightly directly above the 12th fret wire without pressing it down, and pluck. The harmonic is an octave above the open string; tune it in Chromatic mode for a much steadier reading.
- Pluck with your thumb or a pick. It gives a louder, cleaner note than a light finger pluck.
- Move away from fans and air conditioners. Their hum sits in the same range as bass notes.
Tuning from one good string
Every pair of neighbouring bass strings is a perfect fourth apart, so the 5th fret works everywhere: the 5th fret of a lower string should match the next open string up (B string fret 5 = E, E fret 5 = A, A fret 5 = D, D fret 5 = G). When the slow wobble between the two notes disappears, they match.
For other instruments use the guitar tuner or the ukulele tuner, and practise timing with the metronome.
Frequently asked questions
Nothing happens when I play the E or B string.
Many phone and laptop microphones barely pick up sound below 50 Hz. Play through an amp and hold the phone near it. If that still fails, switch to Chromatic and tune the 12th-fret harmonic, which is an octave higher; when the harmonic is in tune, so is the open string.
The reading keeps wobbling.
A low note has a long period, so the tuner needs to hear it for longer. Let the string ring without muting it, and rest your hand on the other strings so they don't resonate.
Can I tune to Drop D or lower?
Use Chromatic mode, which names whatever note you play. For Drop D, bring the E string down to D1 (36.71 Hz).
Does it record me?
No. The sound is analysed live in your browser while the tuner is on; nothing is stored or uploaded.
Privacy
This tool runs entirely in your browser. Your files and text are processed on your device and are never uploaded to our servers.