Five strings, one surprise
Standard bluegrass banjo tuning is Open G — written low to high as g4–D3–G3–B3–D4. Strummed open, it rings a G major chord. The surprise is the 5th string, written with a lowercase g: it’s a short drone string that starts at the fifth fret and runs to its own little peg, tuned to G4 — the highestpitch on the whole instrument despite being called the “5th” string. This tuner reads it exactly like any other note — pluck it and check the letter, octave and cents same as the rest.
If you have a 4-string banjo instead, you have a different instrument rather than a banjo missing a string: a tenor tunes in fifths, a plectrum keeps the 5-string’s long strings and drops the drone, and a 6-string is tuned exactly like a guitar. Pick yours below.
Pick your banjo and tuning, then tap a tone and tune your string until the two sounds merge — or play each string into the tuner above and centre the needle. Highlighted rows are the strings that move from Open G.
The 5-string tunings, and what actually changes
Nearly every open-back and bluegrass tuning is Open G with one or two strings moved. Learning them as differences rather than as five fresh notes is far faster, and it tells you which pegs to touch:
| Tuning | Notes | Changes from Open G | Used for |
|---|---|---|---|
| Open G | g–D–G–B–D | — | Bluegrass standard; open strings sound a G chord |
| Double C | g–C–G–C–D | 4th up to C3, 2nd up to C4 | Old-time C tunes; often capoed up two frets for D |
| Sawmill (G modal) | g–D–G–C–D | 2nd only, B3 → C4 | Modal fiddle tunes — neither major nor minor |
| Open D | f♯–D–F♯–A–D | 5th, 3rd and 2nd all lowered | D tunes with a darker, looser voice |
| Drop C | g–C–G–B–D | 4th only, D3 → C3 | A C bass under otherwise unchanged Open G shapes |
| Double D | a–D–A–D–E | Double C capoed up two frets | The usual way to reach D from double C |
Sawmill is the one worth knowing by name. It differs from Open G by a single half step on the 2nd string, which removes the major third from the open chord — that is what gives the modal, unresolved sound of tunes like Cluck Old Hen, and it is one peg away from where you already are.
Tuning order
- Tune the four long strings first: D3 → G3 → B3 → D4. Check the letter before the needle — the 1st and 4th strings are both D, an octave apart, so the octave display is what keeps them straight.
- Tune the 5th string to G4 last. Its short scale makes it twitchy — small peg moves, and check it twice. Friction pegs on the 5th string are notorious for slipping right after you let go.
- Strum all five openand listen for a clean G major chord. If it sounds sour only when fretted (fine when open), that’s a bridge position problem, not a tuning one — the bridge is held on by string pressure alone and can creep out of place.
Capoing the 5th string
A capo on a 5-string only clamps the four long strings — the 5th starts at the fifth fret, past where any normal capo sits, so it keeps sounding G4 while everything else moves up. There are three standard answers, and all three are asking the 5th string for the same pitch:
| Capo position | Key | 5th string target | Spike |
|---|---|---|---|
| 2nd fret | A | A4 · 440.00 Hz | 7th fret |
| 3rd fret | B♭ | B♭4 · 466.16 Hz | — |
| 4th fret | B | B4 · 493.88 Hz | 9th fret |
| 5th fret | C | C5 · 523.25 Hz | 10th fret |
Railroad spikes are small model-railway spikes tapped into the fingerboard beside the 5th string; you hook the string under one and it frets itself at that position. The usual pair is the 7th and 9th frets, which is exactly the A and B in the table — that is why those two are standard rather than arbitrary. A sliding 5th-string capo mounted on a rail does the same job continuously. And you can simply retune the peg, which is what the numbers above are for: check the target on the dial rather than guessing, because two semitones on a short, twitchy string is a bigger peg movement than it feels like.
Why a banjo drifts more than a guitar
A banjo has a tuning variable no wooden instrument has: the head. It is a membrane stretched over the rim by a ring of brackets, and it responds to humidity and temperature far faster and further than a spruce top does. A skin head is dramatic about it; even a modern plastic one moves. So a banjo left overnight in a dry heated room comes back tighter — the head pulls up, the bridge rides higher, and every string reads sharp with nothing at all wrong. In a damp hall the reverse happens.
Two consequences worth knowing. First, check the whole instrument on arrivalrather than trusting last night’s tuning; a banjo can be uniformly out in one direction, which is unusual and looks alarming. Second, if you are chasing a tuning that will not settle at all over weeks, look at head tension before the pegs — a slack head makes everything vague, and a genuinely over-tight one is how heads split.
The bridge is not attached to anything
A banjo bridge — usually three small feet under a maple-and-ebony blank — is held on the head by string pressure alone. Nothing glues it, and it walks. That gives you one hazard and one adjustment.
The hazard:slacken all the strings at once and the bridge falls over, taking your intonation with it. Change strings one at a time, and mark the bridge’s position with a strip of masking tape before you do anything that might move it.
The adjustment: if the banjo is sweet on open strings and sour by the seventh fret, that is bridge position, not tuning. Compare the harmonic over the 12th fret with the note fretted at the 12th on the 1st and 4th strings. Fretted sharp means the bridge moves back, away from the neck; fretted flat means toward it. Expect the two ends to want slightly different positions, which is why a correctly placed banjo bridge sits at a small angle rather than square across the head.
Tenor, plectrum and 6-string
The three 4- and 6-string banjos are not variants of the 5-string, and each has its own standard:
- Tenor — C3, G3, D4, A4. Four strings in fifths, the same pitches as a viola, on a short neck with no drone. Irish players instead tune G2, D3, A3, E4, an octave below a fiddle, which needs its own heavier string set.
- Plectrum — C3, G3, B3, D4. A 5-string with the drone removed and a full-length neck, so its three top strings match a 5-string exactly.
- 6-string — E2, A2, D3, G3, B3, E4. Guitar tuning on a banjo pot; our guitar tuner page applies to it unchanged.
Two more turn up often enough to be worth naming, and neither is a banjo with a different tuning — they are other instruments wearing a banjo body:
- Eight strings in four pairs — a banjo mandolin(mandolin-banjo, banjolin), tuned G3–D4–A4–E5 in unison courses exactly like a mandolin. If you are counting eight strings and looking for an eight-string banjo tuning, this is almost certainly what you have; the mandolin tuner covers it, including the pair-matching that a single-strung banjo never asks for. (An eight-string tenor banjo — four doubled courses in C–G–D–A — also exists and is far rarer; use the tenor set above and match each pair.)
- Four nylon strings and a short neck — a banjolele, tuned G4–C4–E4–A4 like a soprano ukulele. The ukulele tuner is the page for it, reentrant G and all.
Frequently asked questions
Is there a free banjo tuner app I don’t have to install?
This page is one. It runs in your browser through the microphone — no install, no account, no ads, and the audio is analysed on your device rather than uploaded anywhere. It works the same on a phone propped against the pot, a tablet or a laptop, and the reference tones work even with no microphone at all. Every 5-string, tenor, plectrum and 6-string tuning below is pre-set; you do not need a banjo-specific mode, because the dial names every note there is.
What is standard banjo tuning?
For a 5-string banjo it is Open G, written g–D–G–B–D: G4 on the short 5th string, then D3, G3, B3 and D4 on the four long strings. Strummed open it sounds a G major chord. The lower-case g is the convention for the short drone string, and it is the highest-pitched string on the instrument even though it is called the 5th. A 4-string tenor banjo is a different instrument in C–G–D–A, and a plectrum banjo is C–G–B–D.
Is this a real banjo tuner, or just a generic app?
It’s a chromatic tuner — it names any note it hears rather than only recognizing five fixed targets, which means it works for Open G, double C, sawmill, Open D, tenor, plectrum and 6-string banjos alike, including the 5th-string drone. No banjo-specific mode is needed because the dial already reads letter, octave and cents for every note there is. Pick your tuning in the reference tones for the exact targets.
How do I tune a 4-string tenor banjo?
Standard tenor tuning is C–G–D–A — C3, G3, D4, A4 — in fifths, exactly the same four pitches a viola is tuned to. Irish tenor players instead drop the whole instrument a fourth, to G–D–A–E (G2, D3, A3, E4), so it matches fiddle fingering an octave down, which is a big enough change that it needs its own string gauges. Both sets are in the reference tones above; the octave display is what tells you which one you are actually on.
My 5th string won't hold its tuning. Is that normal?
Very common — most banjos use a friction peg there, which holds by pressure alone. Push it firmly inward while turning, like a violin peg. If it still slips, the small screw in the peg’s end is usually loose; tightening it often fixes things for good, and a geared 5th-string peg is a cheap, permanent upgrade if it keeps happening.