1 sharp key signature: which keys use one sharp?
A 1 sharp key signature is the signature of G major and its relative minor, E minor. The single sharp is F sharp. On the treble staff it stands on the top line. On the bass staff it stands on the fourth line. Count one fifth up from C and you land on G; the tonic pitches you can recompute are 392.00 Hz for G and 329.63 Hz for E.
What a 1 sharp key signature names
G major and E minor are written with one sharp, and that sharp is F sharp. It is printed after the clef and applies to every F on the staff until a natural cancels it. The next sharp in the fixed order would be C sharp, and this signature does not print it. Two sharps is a different page.
| Question | G major | E minor |
|---|---|---|
| Key name | G major | E minor |
| Signs, in order | F sharp only | F sharp only |
| Where F sharp sits | Treble: top line. Bass: fourth line. | Same two places. The minor does not move the sign. |
| Tonic you can recompute | G 4 = 392.00 Hz | E 4 = 329.63 Hz |
| Diatonic triads | G major, A minor, B minor, C major, D major, E minor, F sharp diminished | E minor, F sharp diminished, G major, A minor, B minor, C major, D major |
| G major | E minor |
|---|---|
| G, A, B, C, D, E, F sharp | E, F sharp, G, A, B, C, D |
How to name the key from one sharp
Sharps are added in one order: F, C, G, D, A, E, B. One sharp stops at the first step, F sharp. The major tonic sits a minor second above the last sharp. F sharp up one semitone is G, so the major key is G major.
The same result comes from the circle of fifths. C major has no sharps. Each new sharp moves the major tonic up a perfect fifth, which is seven semitones. One step up from C is G. A second step would reach D, and that signature has two sharps, covered on the 2 sharps key signature page.
E minor is the relative minor: the same signature, with the tonic a minor third under the major tonic. G down three semitones is E. The printed F sharp does not tell you which of the two keys a piece is in. The note the music settles on does.
Numbers you can check
Equal temperament, A 4 = 440 Hz, sets a pitch at 440 × 2((midi − 69) ÷ 12) Hz. G 4 is midi 67: 440 × 2((67 − 69) ÷ 12) = 440 × 2(−2 ÷ 12) = 391.995… Hz, which rounds to 392.00 Hz. E 4 is midi 64: 440 × 2((64 − 69) ÷ 12) = 440 × 2(−5 ÷ 12) = 329.628… Hz, which rounds to 329.63 Hz.
The signature count is a count, not a pitch: the staff shows one sharp, and its name is F sharp. One perfect fifth above C is G. Three semitones below G is E.
Those figures are arithmetic. The recording below is a separate reading. On 20 October 2026 this site’s key finder called the opening of Bach’s G major prelude G major at 29% confidence.
A recorded example you can check
Wikipedia’s article The Well-Tempered Clavier, read on 20 October 2026, lists Book 1 No. 15 as “Prelude and Fugue in G major, BWV 860”. The Open Well-Tempered Clavier score, MuseScore edition by Olivier Miquel, version 1.0 dated 19 March 2015 and marked Creative Commons Zero, prints the heading “Praeludium 15 / BWV 860” and one sharp on the first system: the treble sharp is on the top line, and the bass sharp is on the fourth line. The clip is the opening of that prelude, not the fugue. The key name comes from the article. The single sharp is what that page of the score prints. The two sources do not copy each other: one is a work list, the other is the engraved staff.
On 20 October 2026 at 06:03 EDT this site’s key finder read this 20-second clip as G major, Camelot 9B, at 29% confidence, and labelled the reading low. It listed D major (Camelot 10B, 24%) and B minor (Camelot 10A, 15%) next. The on-screen note says D major also fits and that the melody or chords should be checked before mixing. That percentage is the finder’s estimate for this file, not a measured accuracy rate. The article and the score name the prelude G major, and the finder named G major as well, at low confidence.
What our key tools tell you
Give a recording to the key finder for the key it hears, or drop the chords into key from chords. The printed signature is read from the staff. One sharp on the page is F sharp even when a short clip comes back at low confidence.
1 sharp key signature: quick answers
What key has one sharp?
G major, and its relative minor, E minor. Both use a 1 sharp key signature, and the sharp is F sharp.
Where does the one sharp go?
After the clef. On the treble staff, F sharp is the top line. On the bass staff, F sharp is the fourth line.
How do you get G from one sharp?
The last sharp is F sharp, and the major tonic is one semitone higher, which is G. The same step is one perfect fifth up from C.
What chords belong to G major?
G major, A minor, B minor, C major, D major, E minor, and F sharp diminished. E minor uses those same triads with E minor as the home chord.
What did the finder return for the G major prelude?
G major, Camelot 9B, 29% confidence, marked low. D major at 24% and B minor at 15% were the next two candidates.
What this page leaves open
- This page is only the one-sharp signature. A piece can add accidentals and still be read as G major or E minor.
- 392.00 Hz and 329.63 Hz are equal-temperament arithmetic from A 4 = 440 Hz. They were not measured off the piano recording.
- The 29% figure is this 20-second file only. It is not an accuracy rate for every piece in G major.