Free Bass Tuner With Mic (4 & 5-String, No App)
Tap Start, allow the mic, then pluck one bass string at a time. Tune UP to the pitch (from slightly flat) and mute the other strings.
Tap a string to tune to it (or leave on Auto). Tap the speaker button to hear its reference tone by ear.
Privacy: Mic audio is processed locally in your browser to detect pitch. It is never recorded, uploaded, or stored. The mic stream stops when you press Stop or leave this page. Mic access requires HTTPS (this site is HTTPS). If the mic is denied, use the reference tones: play a string tone, then match your string to it by ear.
How to tune a bass
- Pick Bass, 4-string (E A D G) or Bass, 5-string (B E A D G).
- Pluck one open string firmly and let it ring; rest your other hand lightly on the strings you are not playing.
- If the needle is left of centre the string is flat: tighten it. If it is right, loosen it a little below the note and tune back up.
- Go string by string, then check them all again - the neck settles as tension changes.
Standard bass tuning
| String (thickest first) | Note | Frequency |
|---|---|---|
| 5-string only: low B | B0 | 30.87 Hz |
| 4th (thickest on 4-string) | E1 | 41.20 Hz |
| 3rd | A1 | 55.00 Hz |
| 2nd | D2 | 73.42 Hz |
| 1st (thinnest) | G2 | 98.00 Hz |
Bass strings are the same notes as a guitar's four lowest strings, one octave lower. Tuning a guitar instead? Use the guitar tuner.
If it won't read a low note
- Move the phone or laptop closer to the amp speaker or the bass body.
- Pluck a bit harder and wait a second for the note to settle.
- Try the 12th-fret harmonic: touch the string lightly above the 12th fret and pluck - it shows the same note name one octave up.
- Turn off noise suppression in video-call apps and close other tabs using the mic.
FAQ
Can I tune a bass with my phone's microphone?
Yes. Open this page, tap Start, allow the mic and pluck one string at a time. Get the phone close to the amp or the bass body; laptop and phone mics pick up low notes less well than higher ones.
What are the standard bass tuning notes?
4-string: E A D G, thickest to thinnest (E1 41.2 Hz, A1 55 Hz, D2 73.4 Hz, G2 98 Hz). 5-string adds a low B (B0 30.9 Hz).
Why does the tuner struggle with my low E or B?
Very low notes are hard for small mics. Pluck firmly, let the note ring, play a little closer to the neck, or check the octave harmonic at the 12th fret, which reads the same note name an octave up.
Why can't I hear the reference tone for low strings?
Phone and laptop speakers often cannot reproduce notes as low as E1 or B0. Use headphones or rely on the needle.
Is the bass tuner free?
Yes. It runs in your browser with no signup, and the audio stays on your device.
Find any note with the bass note finder or see the fretboard chart. Learning bass? Start at the bass hub, follow the 4-week bass practice plan, see best online bass lessons and beginner bass gear.
Sources checked
- String frequencies: standard 12-tone equal temperament with A4 = 440 Hz (computed: f = 440 x 2^((n-69)/12)).
- Tuning uses are general descriptions in our own words.
Not hands-on testing: troubleshooting steps are general guidance, not product tests.
Related step-by-step guides
- Best guitar tuner app - free app options compared, and how to tune with a phone.