3 Flats Key Signature: Which Keys Have Three Flats?
A 3 flats key signature means E flat major or its relative minor, C minor. The three flats are B flat, E flat and A flat, always in that order. Both keys lean on the identical three signs, so you tell them apart by whichever note feels like home. Below: the three flats drawn and labelled, the scale notes for both keys, and the pitches you can check.
What 3 flats key means
E flat major and its relative C minor are written with three flats: B flat, E flat, A flat. These three flats are printed once after the clef and hold for the whole line unless a natural, sharp or flat sign cancels one of them.
| Question | Major key | Relative minor |
|---|---|---|
| Key name | E flat major | C minor |
| Sharps or flats | three flats: B flat, E flat, A flat | three flats: B flat, E flat, A flat |
| Tonic pitch | E flat major: 311.13 Hz | C minor: 261.63 Hz |
| How they are written | Flats are added in the fixed order B, E, A, D, G, C, F, so a three-flat signature stops after the third step, A flat, and never reaches D flat. | Flats are added in the fixed order B, E, A, D, G, C, F, so a three-flat signature stops after the third step, A flat, and never reaches D flat. |
| E flat major | C minor |
|---|---|
| E flat, F, G, A flat, B flat, C, D | C, D, E flat, F, G, A flat, B flat |
How to read this signature
Flats always get laid down in one sequence — B, E, A, D, G, C, F — and a three-flat signature simply stops after the third step, at A flat. Nothing else is ever added.
Flats are added in the fixed order B, E, A, D, G, C, F, so a three-flat signature stops after the third step, A flat, and never reaches D flat.
E flat major and C minor lean on the same three flats, so the printed signs alone never reveal which of the two a piece is in.
Numbers you can check
The three flats sit at three measurable pitches: the tonic of E flat major, E flat 4 = 311.13 Hz, and of C minor, C 4 = 261.63 Hz (equal temperament, A4 = 440 Hz). Counting the accidentals on this signature gives three — B flat, E flat, A flat — and no more.
Equal temperament from A4 = 440 Hz sets any note n semitones above A4 at 440 × 2n/12 Hz; rerun that to verify the two tonic figures above.
Those frequencies are arithmetic. A separate reading of one recording is in the example: on 16 October 2026 the key finder called the opening of Bach’s E flat major prelude E flat major at 73% confidence.
A recorded example you can check
Wikipedia’s The Well-Tempered Clavier article, read on 16 October 2026, heads Book 1 No. 7 as “Prelude and Fugue in E flat major, BWV 852”. The Open Well-Tempered Clavier score, MuseScore edition version 1.0 dated 19 March 2015 and marked CC0, prints three flats — B flat, E flat, A flat — between the clefs and the time signature on the first page of Praeludium 7. That is the same signature as C minor. The recording below is the opening of that prelude. The key name comes from the article; the three flats are what that page of the score prints.
On 16 October 2026 this site’s key finder read this 20-second clip as E flat major, Camelot 5B, at 73% confidence, and listed C minor (7%) and F minor (5%) as the next two candidates. That percentage is the finder’s estimate for this file, not a measured accuracy rate.
What our key tools tell you
Feed a recording to the key finder to hear which of the two keys it suggests, or list the chords and let key from chords decide. This page is about reading the printed signature.
3 flats key signature: quick answers
What key has 3 flats?
E flat major and its relative minor, C minor. Both are written with the same three flats: B flat, E flat and A flat.
Is 3 flats E flat major or C minor?
Both. Three flats is the signature shared by E flat major and C minor. The last note, and the chord the piece settles on, tell you which one you are in.
What are the 3 flats in order?
B flat, E flat and A flat. Flats always arrive in the order B, E, A, D, G, C, F, so a three-flat signature is just the first three of that list.
What is the relative minor of E flat major?
C minor. Relative keys share a key signature, so C minor uses the same three flats as E flat major.
What does a 3 flat key signature look like?
Three flat signs on the B, E and A lines and spaces right after the clef, then nothing else changes for the rest of the line.
What this page leaves open
- This page covers the printed three-flat signature; modulating out of it with accidentals is a separate topic.
- The tonic frequencies are computed in equal temperament, not measured from a performance.
- The enharmonic spelling of the same pitches (D sharp rather than E flat) is not treated here.