Bass tuner
Low notes, read properly.
–
–cents
Strings
Tap a string to hear its note and tune to it; tap again to go back to automatic
Nothing leaves your device
This tool runs entirely in your browser. What you type, play or record here stays on your device: nothing is uploaded or saved on a server.
Example
Example: new strings on a 4-string bass, and a slack A string read as an E
You have just fitted new strings and every one is far below pitch. Reference A4 = 440 Hz, bass played unplugged next to the laptop microphone. The page compares each note with the nearest of E1, A1, D2 and G2 — and a very slack string can be nearer the wrong one.
- Pluck the A string: it sounds at 46.0 Hz, an F♯1. That is 191 cents above E1 and 309 below A1, so the tuner shows E, needle hard right, “Too high — loosen”. Don’t loosen it.
- Tap A under Strings: you hear A1, and the tuner now measures against it: −309 cents, needle hard left, “Too low — tighten”.
- Tighten: at 52.0 Hz it still reads −97 (a G♯1), at 54.6 Hz −13 with the needle on the dial. “In tune” lights green once it holds within ±3 cents for 0.6 s.
- Tap A again to go back to automatic, then tune E, D and G. New strings stretch, so go round all four a second time.
| String | In tune at | Slack new string | What the tuner shows |
|---|---|---|---|
| E (thickest) | E1, 41.20 Hz | 38.0 Hz | E, −140 cents, Too low — tighten |
| A | A1, 55.00 Hz | 46.0 Hz | E, +191 cents, Too high — loosen (tap A to lock it) |
| D | D2, 73.42 Hz | 70.0 Hz | D, −82 cents, Too low — tighten |
| G (thinnest) | G2, 98.00 Hz | 97.0 Hz | G, −18 cents, Too low — tighten |
Only a string more than about 250 cents flat — halfway to the next string down — is read against the wrong one, and tapping the string fixes that. Once all four rest at 0 within ±3 cents, the bass is in tune at A = 440 Hz.
How it works
- Press Start tuner and allow the microphone; a laptop or phone microphone is fine.
- Pluck one string firmly and let it ring: the tuner listens long enough to catch the low E.
- Turn the peg until the needle is centred and “In tune” lights up.
Frequently asked questions
- What are the notes of a bass guitar?
- On a 4-string bass, from the thickest string: E1 A1 D2 G2 — an octave below the guitar’s four lowest strings. A 5-string adds a low B0.
- Can a phone microphone hear a bass?
- Yes. Small microphones barely pick up the fundamental, but the tuner reads the pitch from the harmonics too. Pluck near the neck for a rounder tone.
- Why does the tuner not hear anything?
- The browser needs permission to use the microphone — press Start and allow it, or check the icon next to the address bar. Play one string at a time, close to the phone or laptop, in a quiet room.
- Can I tune a 5-string bass?
- Its four strings E A D G, yes. The low B of a 5-string (B0, 30.87 Hz) is heard, but this page measures every note against the nearest of its strings, the E: the needle sits hard left at −500 cents with “Too low — tighten”, which you must not follow. Tune the low B with the chromatic tuner, which reaches down to B0 and shows the cents from that note.
- Why does it tell me to loosen a string that is far too slack?
- It measures each note against the nearest string. An A string down at 46 Hz is nearer the E (+191 cents) than the A (−309 cents), so it reads as a sharp E. Tap A under Strings to lock the tuner on that string; tap it again to go back to automatic.
- Can I tune my bass to drop D?
- Not with this page’s needle: a low string at D1 (36.71 Hz) is measured against E1 and stays at −200 cents with “Too low — tighten”. Use the chromatic tuner, which names the nearest note and shows D1 at 0 cents.
- Is my playing recorded?
- No. The sound is analysed in your browser as it comes in and is never recorded or uploaded.
Made for a specific use
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