Bb Major
Key Signature
| Property | Value |
|---|---|
| Tonic | Bb |
| Mode | Major |
| Accidentals | 2 flats |
| Key Signature Notes | Bb, Eb |
Bb major has two flats (Bb, Eb) and is extremely common in jazz and wind ensemble music. It is the home key for Bb instruments such as the trumpet and tenor saxophone.
Diatonic Chords
The seven diatonic chords of Bb Major — each built on a scale degree using only the notes of the key signature:
| Degree | Roman Numeral | Chord Type | Chord |
|---|---|---|---|
| 1 | I | Major | Bb Major |
| 2 | ii | Minor | C Minor |
| 3 | iii | Minor | D Minor |
| 4 | IV | Major | Eb Major |
| 5 | V | Major | F Major |
| 6 | vi | Minor | G Minor |
| 7 | vii° | Diminished | A Diminished |
Related Keys
- Relative Minor
- G Minor — shares the same key signature.
- Parallel Minor
- Bb Minor — same tonic, different key signature.
See all key relationships on the Circle of Fifths.
Scales in Bb Major
Common scales built from the Bb tonic:
Transposing Instrument Context
Bb instruments (trumpet, clarinet, tenor saxophone) read in C major to sound Bb Major. Eb instruments (alto saxophone, Eb clarinet) read in G major to sound Bb Major. Flat-key signatures are particularly comfortable for woodwind instruments designed around Bb and Eb transpositions.