Bass tuner
Four strings E A D G, or five with a low B. Tap Start tuner and play one string at a time.
Play a string
Tune with your microphone
We listen through your microphone to hear the pitch. Audio stays on this device: nothing is recorded or sent.
Allow the microphone
Your browser is asking for permission. Choose “Allow” in its prompt and the tuner starts listening.
The microphone is blocked
The browser did not let the tuner hear you. You can allow it again in a few taps, or tune by ear with the reference notes.
Chrome or Edge on a computer
Click the icon to the left of the address bar (a slider or a padlock), switch Microphone to Allow, then reload the page.
Safari on a Mac
Open Safari › Settings for This Website (or Safari › Settings › Websites › Microphone), set this site to Allow, then reload.
iPhone or iPad
Open Settings › Safari › Microphone and choose Ask or Allow. In Chrome for iOS: Settings › Chrome › Microphone. Then come back and tap Try again.
Android
Tap the icon next to the address, open Permissions and allow Microphone. If it is still blocked, open Android Settings › Apps › Chrome › Permissions › Microphone.
Firefox
Click the microphone icon with a slash in the address bar, remove the block for this site, then reload the page.
No microphone found
Plug in a headset or use a phone or laptop with a built-in microphone. Until then, the reference notes let you tune by ear.
Another app is using the microphone
Close the call, recorder or other tab that holds the microphone, then try again.
The microphone needs a secure page
Browsers only open the microphone on https pages. Open this page via https to use the tuner.
All strings in tune. Happy playing!
Reference notes
Tap a note, play the same string and turn the peg until the two sounds stop “beating” against each other.
Bass tuning: notes and frequencies
A 4-string bass is tuned E A D G, exactly like the four lowest strings of a guitar but one octave lower: the open E sounds at 41.20 Hz and the G at 98 Hz. A 5-string adds a low B at 30.87 Hz below the E. These are very low frequencies, and a phone or laptop microphone hears them mostly through their overtones. That is why this page uses a longer listening window and a harmonic check, so it locks onto the real note rather than the octave above.
| String | Note | Frequency (Hz) | MIDI |
|---|---|---|---|
| 4 | E₁ | 41.20 | 28 |
| 3 | A₁ | 55.00 | 33 |
| 2 | D₂ | 73.42 | 38 |
| 1 | G₂ | 98.00 | 43 |
| String | Note | Frequency (Hz) | MIDI |
|---|---|---|---|
| 5 | B₀ | 30.87 | 23 |
| 4 | E₁ | 41.20 | 28 |
| 3 | A₁ | 55.00 | 33 |
| 2 | D₂ | 73.42 | 38 |
| 1 | G₂ | 98.00 | 43 |
Frequencies in equal temperament with A4 = 440 Hz. If you calibrate A4, the tuner shifts every target with it.
How to tune a bass, string by string
- Choose 4-string or 5-string above. On a 5-string, start with the low B and give it a full second to settle on the gauge.
- Tune the E string (41.20 Hz). Pluck firmly with the side of a finger near the end of the neck, where the fundamental is strongest.
- Tune the A (55 Hz), then D (73.42 Hz) and G (98 Hz). Mute the strings you are not tuning with your left hand so they do not ring along.
- Go through all strings again. Bass strings are heavy and the neck moves noticeably when the tension changes.
Tips for the bass
- If the tuner struggles with the low B or E, play the 12th-fret harmonic instead (touch the string lightly over the 12th fret and pluck). It sounds one octave up, which the microphone hears better; Chromatic mode shows it as E2 or B1.
- Electric bass through an amp: hold the phone near the speaker, not the strings. Unplugged, put the microphone close to the bridge pickups.
- Flatwound and new roundwound strings both need a day of stretching; retune a few times during your first session.
- Tune up to the note, as on a guitar: drop below and come back up so the tuning gear holds.
If the tuner does not react
- Nothing happens after Start: look for the browser’s permission prompt (top of the screen on a computer, bottom on Android) and choose Allow.
- The note jumps around: play one string at a time, let the others ring out or mute them, and pluck a little harder.
- It shows the right note an octave off: that is the second harmonic. Pluck over the neck rather than at the bridge, and wait half a second.
- Blocked by mistake? The panel that appears tells you how to allow the microphone in your browser.
Questions and answers
Why is the low B so hard for a phone to hear?
Its fundamental is about 31 Hz, below what small speakers and many phone microphones capture well. The tuner reconstructs the pitch from the harmonics and uses a window long enough to cover several full vibrations, so it needs a second longer than on the higher strings.
Can I use the guitar tuner for bass?
You can in Chromatic mode, but the Bass setting is better: it targets the bass notes directly and analyses a longer stretch of sound, which makes the low strings steadier.
What about drop D on bass?
Lower the E string a whole step to D (36.71 Hz) and use Manual or Chromatic mode to check it. The other strings stay the same.
Is my audio recorded or sent anywhere?
No. The sound from the microphone is analysed in your browser, a few thousandths of a second at a time, and thrown away. Nothing is recorded, stored or uploaded. The microphone switches off when you tap Stop, when you leave the page and after two minutes of silence.