Online Bass Tuner
Press Start, play one open string, turn the peg until it says In tune.
Bass tuner
The tuner needs JavaScript and a microphone. The note table and frequencies below work without it.
Uses your microphone. Nothing is recorded.
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Microphone is blocked
The tuner can’t hear your bass until you allow the microphone for this site. 1. Open the site settings for this page (steps for your browser below). 2. Set Microphone to Allow, then press Try again.
No microphone found
Plug in or switch on a microphone, or use a phone or laptop with a built-in one, then press Try again.
The microphone is busy
Close other apps or tabs that use it, such as video calls or recorders, then press Try again.
No microphone access in this browser
Use a current version of Chrome, Edge, Firefox or Safari, and check that the address starts with https://.
The microphone could not start
Reload the page and press Try again.
Chrome on a computer
Click the icon to the left of the web address, set Microphone to Allow, then reload the page.
Microsoft Edge
Click the lock icon to the left of the web address, open Permissions for this site, set Microphone to Allow and reload.
Firefox
Click the crossed-out microphone icon in the address bar, clear the blocked permission, reload and choose Allow when asked.
Safari on a Mac
Open Safari, Settings, Websites, Microphone, and set onlinebasstuner.app to Allow or Ask. Then reload the page.
iPhone or iPad
Tap the page menu (aA) in the address bar, open Website Settings and set Microphone to Allow or Ask. Then reload the page.
Chrome on Android
Tap the icon to the left of the web address, open Permissions and turn on Microphone. Then reload the page.
Or tune by ear: tap a string button below to hear its note, or use the reference tones ↓.
Reference pitch A4 = 440 Hz
This free online bass tuner listens through your microphone and shows how far each string is from its note. Standard 4-string bass tuning, from the thickest string, is E1, A1, D2 and G2. Pick 5-string, 6-string, Drop D or Drop C above, or tap a string to hear its note.
Standard bass tuning
| String | Note | Hz | Octave |
|---|---|---|---|
| 4 | E | 41.20 | 1 |
| 3 | A | 55.00 | 1 |
| 2 | D | 73.42 | 2 |
| 1 | G | 98.00 | 2 |
A 5-string adds a low B (30.87 Hz) below the E, and a 6-string adds a high C (130.81 Hz) above the G. See 5-string and 6-string tuning.
Why bass is harder to tune than guitar
The low E of a bass vibrates about 41 times per second, and a low B about 31 times. A tuner needs a longer slice of sound to measure such slow waves, and small microphones hear these deep notes weakly. This tuner uses a longer analysis window than a guitar tuner and searches down to 27 Hz, below the low B. Let each note ring for a second or two before you judge the needle.
Quick tips
- Tune up to the note: if a string is sharp, go below the note first, then come up to it. The string holds its pitch better.
- Pluck with your finger at a normal strength. Very hard plucks start sharp for a moment.
- Mute the other strings with your fretting hand so only one rings.
- Check all strings again at the end. Changing one string slightly changes the tension on the neck.
Reference tones (tune by ear)
Reference tones need JavaScript.
Tap a string to hear its note, tap again to stop. No microphone needed.
4-string (E A D G)
Questions and answers
How do I tune my bass online?
Press Start tuner and allow the microphone. Play one open string and let it ring. The tuner shows the nearest string and how many cents you are off. Turn the tuning peg until the needle is in the centre and the display says In tune, then go to the next string.
What are the notes of a standard bass?
A 4-string bass is tuned E A D G from the thickest string: E1 (41.20 Hz), A1 (55.00 Hz), D2 (73.42 Hz), G2 (98.00 Hz). These are one octave below the four lowest strings of a guitar.
Can a phone microphone hear a low B string?
Often, yes, but not always well. Phone and laptop microphones pick up very little at 31 Hz, so the tuner mostly hears the overtones of the string. If a low B or a low C will not read, hold the phone close to the speaker or the bass, pluck a little harder, and tap the string button to lock the tuner to it.
Is the microphone private?
Yes. The browser only gives the page microphone access after you allow it. The sound is analysed on your own device, nothing is recorded, saved or uploaded, and the microphone switches off when you press Stop or leave the page.
Does it work with an electric bass without an amp?
Yes. An unplugged electric bass is quiet, so hold the phone or laptop close to the strings, near the pickups or the body. Through an amp it is easier: put the microphone near the speaker and keep the volume moderate.
More bass tools
- 4-string bassE A D G
- 5-string bassB E A D G
- 6-string bassB E A D G C
- Drop D and lowerDrop D, D standard, half step down, Drop C
- Reference tonesTune by ear
- How to tune a bassStep by step
- Acoustic bassTuning without a cable
- Ukulele bassRubber and nylon strings
- Online guitar tunerSister site for guitar
Last updated October 23, 2026.