G Dominant 7th Chord

What is a G7 chord?

A dominant 7th adds the flat 7 to a major triad — root, major 3rd, perfect 5th and minor 7th. That flat 7 creates an unresolved tension (the tritone between the 3rd and the b7) that 'wants' to resolve down a fifth. This is the engine of every V-I cadence in jazz and the foundation of every 12-bar blues progression where every chord is dominant.

Where G7 fits in a key

G7 appears as the V7 in C major.

Common progressions with G7

When to use a dominant 7th chord

G7 has the strongest pull of any chord toward C — it's the V7 of C major. Dominant 7ths are the V chord in countless major-key songs, where they pull strongly back to the I (G7 → C in C major). In 12-bar blues, every chord is dominant — I7, IV7 and V7 — for that bluesy, unresolved cycle. They also appear as secondary dominants ('V of V') to tonicize chords mid-progression, e.g. D7 leading to G in C major.

Common substitutions for G7

• •Dominant 9 — adds the 9 for a fuller, jazz-funk sound
• •Dominant 13 — adds the 13 for soul and gospel voicings
• •Altered dominant (7#5, 7b9) — for outside, jazz-fusion tension
• •Tritone substitution — replace V7 with bII7 for a chromatic resolution