I-IV-V (the Three Chord Trick)
I · IV · V
The most fundamental progression in Western music.
Key of C#
The Key of C♯ Major
The chords in the key of C♯ major are C♯, D♯m, E♯m, F♯, G♯, A♯m and B♯dim.
Seven sharps — the sharp-side twin of Db major.
Below: all seven diatonic chords with guitar shapes and audio, the scale, the key signature (F♯ · C♯ · G♯ · D♯ · A♯ · E♯ · B♯), 8 progressions already transposed into this key, and the keys next door.
Diatonic chords
The 7 chords in the key of C♯ major
Each degree of the C♯ major scale carries one chord. Roman numerals show the degree; the function column tells you what the chord does. Every name links to its full chord page — press play to hear it on guitar.
| Degree | Function | Chord | Guitar shape | Hear it |
|---|---|---|---|---|
| I | TonicTonicHome — rests | C♯D♭ · F · A♭spelled C♯ in C# major · the chord page is D♭ Major | ||
| ii | SubdominantSupertonicDeparts — sets up the V | D♯mE♭ · G♭ · B♭spelled D♯m in C# major · the chord page is E♭ Minor | ||
| iii | TonicMediantHome — rests | E♯mF · A♭ · Cspelled E♯m in C# major · the chord page is F Minor | ||
| IV | SubdominantSubdominantDeparts — sets up the V | F♯F♯ · A♯ · C♯ | ||
| V | DominantDominantPulls back to I | G♯A♭ · C · E♭spelled G♯ in C# major · the chord page is A♭ Major | ||
| vi | TonicSubmediantHome — rests | A♯mB♭ · D♭ · Fspelled A♯m in C# major · the chord page is B♭ Minor | ||
| vii° | DominantLeading tonePulls back to I | B♯dimC · E♭ · G♭spelled B♯dim in C# major · the chord page is C Diminished |
Want the same chords on another instrument? Every chord page carries piano, ukulele, bass, mandolin and banjo shapes — start with piano.
Character
Why songs live in C♯ major
C# major raises all seven letters, which means writing E# and B# where a reader expects F and C. It sounds exactly like Db major, and Db is what publishers almost always print. C# major survives where the surrounding music is already sharp-side: as the relative major of A# minor, or as the key you land in when F# major keeps rising.
Scale
The C♯ major scale
Seven notes, in order from the tonic. Tap any note to hear it, or play the whole scale ascending.
Fretboard patterns and full scale reference: C# Major (Ionian).
Key signature
The C♯ major key signature
F♯ · C♯ · G♯ · D♯ · A♯ · E♯ · B♯
C♯ major is written with 7 sharps. Every F, C, G, D, A, E and B in the music is played sharp unless an accidental says otherwise. Its relative minor, A♯ minor, shares this signature exactly.
Progressions
Chord progressions in C♯ major
The most-used progressions, already transposed into C♯ major. Every chord links to its own page; the progression name opens the full breakdown.
I-V-vi-IV (the Pop Punk Progression)
I · V · vi · IV
The 4-chord pop progression that powers thousands of hits.
vi-IV-I-V (Sensitive Female)
vi · IV · I · V
The minor-flavored sibling of I-V-vi-IV.
I-vi-IV-V (the Doo-Wop)
I · vi · IV · V
The 1950s ballad backbone.
I-IV-I-V
I · IV · I · V
Classic 4-bar phrase with a leading-tone pull on bar 4.
I-♭VII-IV (Mixolydian Rock)
I · ♭VII · IV
Mixolydian flavor; classic rock pull.
12-Bar Blues
I · I · I · I · IV · IV · I · I · V · IV · I · V
The defining blues form. 4 bars I, 2 bars IV, 2 bars I, 1 bar V, 1 bar IV, 1 bar I, 1 bar V (turnaround).
8-Bar Blues
I · V · IV · IV · I · V · I · V
Compressed blues form.
FAQ
Questions about the key of C♯ major
- What chords are in the key of C# major?
- The key of C# major contains seven diatonic chords: C# (I), D#m (ii), E#m (iii), F# (IV), G# (V), A#m (vi), B#dim (vii°). Most songs in C# major lean on C#, F# and G# — the tonic, subdominant and dominant.
- What is the relative minor of C# major?
- A# minor is the relative minor of C# major. Both keys share the same key signature (7 sharps) and exactly the same seven notes — A# minor simply treats A# as home instead of C#, which is why you can borrow chords freely between them.
- What are the easiest chords in C# major to play on guitar?
- C# major has no open guitar shapes — every diatonic chord needs a barre or a movable grip in standard tuning. Most guitarists capo and play open shapes from an easier key instead.
Learn the theory
Read up on C♯ major
This page is the reference. These are the guides that explain how a key works in the first place — read one and the table above stops needing to be looked up.