17 chords (including enharmonic equivalents)
ANATOMY
Dominant 7th Chord Formula
The 4 scale degrees that form every dominant 7th chord — in any key.
I
Root0 st
III
Major 3rd+4 st
V
Perfect 5th+7 st
♭VII
Minor 7th+10 st
A dominant 7th chord is a major triad with a minor 7th stacked on top. The major third and perfect fifth give it a major-chord foundation, but the flat seventh introduces tension that begs to resolve — which is exactly why dominant 7ths are the engine of blues and the V chord of nearly every key.
Applied to G: G (root) – B (major 3rd) – D (perfect 5th) – F (minor 7th). Applied to C: C – E – G – B♭. Applied to E: E – G# – B – D.
About this tool
About 7th Chords on Guitar
The "7th chord" — short for dominant 7th — is the most musically loaded of the basic four-note chords. Its formula combines a major triad with a flat seventh, creating an inherent tension that wants to resolve to another chord. That tension is the foundation of blues (where every chord is a dominant 7th), the V → I cadence of classical and jazz, and countless rock and funk riffs. Once you can play 7th chords across the neck, you have a passport to genres that "just plain major and minor" can't access.
- 01Built from 4 notes: root, major 3rd, perfect 5th, minor 7th (formula 1 – 3 – 5 – ♭7)
- 02Tense, unresolved sound — the chord naturally pulls toward another chord a perfect 4th higher
- 03The defining chord type of blues — every chord in a 12-bar blues (I, IV, V) is a dominant 7th
- 04G7 → C is the textbook "perfect cadence" of Western music — countless songs end on this resolution
- 05Written with a number 7 after the root letter: C7, D7, G7 — no "dom" or "dominant" appears in the chord symbol
- 06E7, A7, B7, and D7 are the four standard open voicings; barre versions cover the rest of the fretboard
- 07Distinct from major 7 (Cmaj7, with a natural 7th) and minor 7 (Cm7, with a flat 3rd) — three chord types share the "7" suffix but differ in formula