Chords in the I IV V I Progression

I IV V I in the Major Keys

Key I IV V I
C major C F G C
G major G C D G
D major D G A D
A major A D E A
E major E A B E
B major B E F# B
F# major F# B C# F#
Gb major Gb Cb Db Gb
Db major Db Gb Ab Db
Ab major Ab Db Eb Ab
Eb major Eb Ab Bb Eb
Bb major Bb Eb F Bb
F major F Bb C F

i iv V i in Minor Keys

Key i iv V i
A minor Am Dm E Am
E minor Em Am B Em
B minor Bm Em F# Bm
F# minor F#m Bm C# F#m
C# minor C#m F#m G# C#m
G# minor G#m C#m D# G#m
D# minor D#m G#m A# D#m
Eb minor Ebm Abm Bb Ebm
Bb minor Bbm Ebm F Bbm
F minor Fm Bbm C Fm
C minor Cm Fm G Cm
G minor Gm Cm D Gm
D minor Dm Gm A Dm

Note that the V chord is often replaced with V7 in both the major and minor key progressions.