Bass Tuner
Tune a bass guitar online with your microphone. Standard 4-string bass tuning is E A D G, with the low E at 41.20 Hz, one octave below the guitar. This tuner also covers 5-string bass (B E A D G) and Drop D. Audio stays on your device.
Bass tuner
The tuner needs JavaScript and a microphone. The note table and reference frequencies below work without it.
To hear the string you play and measure its pitch. When you press Start, your browser asks for permission. The sound is analysed on this device only: nothing is recorded, saved or uploaded, and the microphone switches off when you press Stop or leave the page.
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Press Start tuner, then play one string
String (Auto finds it for you)
Reference pitch: A4 = 440 Hz
The microphone is blocked for this site. The tuner cannot hear your guitar until you allow it. Nothing else on the page needs it, and you can still use the reference tones below to tune by ear. To allow the microphone:
No microphone was found. Plug in or switch on a microphone (or use a phone or laptop with a built-in one), then press Start again.
The microphone is busy. Close other apps or tabs that use it, such as video calls or recorders, then press Start again.
This browser cannot give the page microphone access. 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 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 the page and choose Allow when asked.
Safari on a Mac
Open Safari, Settings, Websites, Microphone, and set onlineguitartuner.app to Allow or Ask. Then reload the page.
iPhone or iPad
Tap the page menu (aA or the settings icon) 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.
Reference tones (tune by ear)
Reference tones need JavaScript.
Press a string to hear its note. Press it again to stop. No microphone needed.
Bass tunings and frequencies
| Tuning | String 5 | String 4 | String 3 | String 2 | String 1 |
|---|---|---|---|---|---|
| 4-string bass | – | E1 41.20 Hz | A1 55.00 Hz | D2 73.42 Hz | G2 98.00 Hz |
| 5-string bass | B0 30.87 Hz | E1 41.20 Hz | A1 55.00 Hz | D2 73.42 Hz | G2 98.00 Hz |
| Bass Drop D | – | D1 36.71 Hz | A1 55.00 Hz | D2 73.42 Hz | G2 98.00 Hz |
The 4-string bass uses the same note names as the four lowest guitar strings, one octave lower. A 5-string bass adds a low B below the E. In Drop D the lowest string goes down a whole step, from E to D.
Tips for tuning bass with a microphone
- Phone and laptop microphones hear low notes weakly. Hold the device close to the speaker cabinet or to the body of the bass.
- Pluck firmly and let the note ring. The tuner needs a few cycles of the wave, and the low B (about 31 Hz) has long cycles.
- If the reading jumps, play the harmonic at the 12th fret. It is the same note one octave up and is easier to detect; Auto mode may then show the next string up, so pick the string by hand.
Questions and answers
How do I tune a bass guitar online?
Choose your bass tuning, press Start tuner and allow the microphone. Play one open string and let it ring, then tighten or loosen it until the display says In tune. Low notes take a moment longer to read, so let the string sustain.
What are the notes of a 4-string bass?
Standard bass tuning is 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 guitar strings.
Why is my bass hard to detect?
Bass notes are low, and many phone and laptop microphones pick them up weakly. Hold the device near the bass amp or the body of the instrument, play a little harder, and if needed tune using the 12th-fret harmonic, which sounds one octave higher.
Last updated October 20, 2026.