C♯ Major 13th = Root + Major 3rd + Perfect 5th + Major 7th + Major 2nd + Perfect 4th + Major 6th = C♯, E♯, G♯, B♯, D♯, F♯, A♯
Note
Interval
Degree
C♯
Root
1
E♯
Major 3rd
3
G♯
Perfect 5th
5
B♯
Major 7th
7
D♯
Major 2nd
9
F♯
Perfect 4th
11
A♯
Major 6th
13
Key Signature
A chord has no key signature of its own, but the C♯ Major 13th is the tonic (I) chord of C♯ Major, whose key signature has 7 sharps (F♯, C♯, G♯, D♯, A♯, E♯, B♯).
F♯C♯G♯D♯A♯E♯B♯
Order of sharps
Sharps are added to a key signature in a fixed order. Each new sharp key adds the next sharp on the list.
F♯C♯G♯D♯A♯E♯B♯
Mnemonic:Father Charles Goes Down And Ends Battle
Chords in the Key of C♯ Major
These are the triads built on each degree of C♯ Major:
The notes C♯ – E♯ – G♯ – B♯ – D♯ – F♯ – A♯ aren’t exclusive to this chord. Depending on which note is the bass and how the chord functions, the same pitches also spell the following: