Bass Tuner
Choose your bass tuning, press Start tuner and pluck an open string: the needle shows how many cents it is flat or sharp and turns green when it is in tune. The detector is built for low notes down to the low B, and every string has a reference tone.
Press Start tuner and allow the microphone, then play one string.
Pluck one open string at a time with your finger or a pick and let it ring; low strings need a second to settle. An amp or a clip-on mic near the bass helps with laptop microphones. Everything runs in your browser — the microphone audio never leaves your device.
How to use the Bass Tuner
- Choose your tuning, for example 4-string standard (E A D G) or 5-string (B E A D G).
- Press Start tuner and allow microphone access when your browser asks.
- Pluck one open string firmly and let it ring. Auto detect picks the nearest string; switch to Manual string to tune one at a time.
- Follow the needle: left of centre is flat (tighten), right is sharp (loosen). Stop when it turns green.
- Tune by ear if you prefer: tap a string to hear its reference tone, or tick the octave-higher option on small speakers.
Bass guitar string frequencies
All target frequencies follow the equal-temperament formula f = A4 × 2(n − 69) / 12 with n the MIDI note number. Changing the A4 calibration moves every string by the same number of cents.
| String | Note | Frequency (A4 = 440 Hz) | Used on |
|---|---|---|---|
| Low B | B0 | 30.87 Hz | 5- and 6-string basses |
| E | E1 | 41.20 Hz | All standard basses |
| A | A1 | 55.00 Hz | All standard basses |
| D | D2 | 73.42 Hz | All standard basses |
| G | G2 | 98.00 Hz | All standard basses |
| High C | C3 | 130.81 Hz | 6-string basses |
Bass tunings at a glance
| Tuning | Notes (low → high) | Lowest note | Typical use |
|---|---|---|---|
| 4-string standard | E1 A1 D2 G2 | 41.20 Hz | Almost all styles |
| 5-string standard | B0 E1 A1 D2 G2 | 30.87 Hz | Modern pop, gospel, metal, worship |
| Drop D | D1 A1 D2 G2 | 36.71 Hz | Rock and metal riffs on a 4-string |
| Half-step down | E♭1 A♭1 D♭2 G♭2 | 38.89 Hz | Matching guitars tuned down a semitone |
| D standard | D1 G1 C2 F2 | 36.71 Hz | Heavier rock, grunge |
| Drop C | C1 G1 C2 F2 | 32.70 Hz | Metalcore and hard rock |
| 5-string drop A | A0 E1 A1 D2 G2 | 27.50 Hz | Extended-range metal |
Why low notes need a special tuner
A pitch detector needs to see several complete cycles of a wave to measure it. The low B string vibrates only 31 times per second, so one cycle lasts 32 milliseconds. This bass tuner therefore analyses a long window of about a third of a second, filters out everything above 420 Hz (pick noise, fret buzz and high overtones) and works on a downsampled signal so it stays fast. It can still find the fundamental when a small microphone hardly picks it up, because the overtones of a string repeat at the same period. Tuning by harmonics also works: the 12th-fret harmonic of each string is exactly one octave above the open string.
Frequently asked questions
What are the standard bass guitar notes?
A 4-string bass is tuned E1, A1, D2, G2 from the thickest string, the same notes as the four lowest guitar strings but one octave lower. With A4 = 440 Hz that is 41.20, 55.00, 73.42 and 98.00 Hz. A 5-string adds a low B0 at 30.87 Hz and a 6-string adds a high C3 at 130.81 Hz.
How do I tune a bass to drop D?
Select Drop D (D A D G) and lower only the E string by a whole step until the tuner shows D1 (36.71 Hz) in the green zone. Check it against the open D string, which should sound exactly one octave higher.
Why is it hard to tune the low B string with a phone?
Phone and laptop microphones pick up very little below about 50 Hz, so the low B (31 Hz) and E (41 Hz) mostly reach the tuner through their overtones. Pluck firmly, hold the mic close to the bridge or use an amp, and give the note a second to settle; the tuner analyses a long 1/3-second window to lock onto low notes.
Why can't I hear the reference tone of the low strings?
Small speakers cannot reproduce very low bass notes. Tick “Play reference tones one octave higher” to hear the same note an octave up, or use headphones.
Should I tune up or down to the note?
Always finish by tuning up to the note. If a string is sharp, loosen it slightly below the note and then bring it up. This keeps the string tension stable in the tuning peg so it stays in tune longer.
Does this work with an electric bass?
Yes. Play the unplugged bass close to the microphone, or play through an amp in the same room. For the most stable reading use the neck pickup and pluck with the fleshy part of your finger.
Is the microphone audio recorded?
No. The microphone signal is analysed live in your browser and is never recorded, stored or uploaded.