Chord Calculator
Find the notes in any chord by root note and type.
Covers major, minor, diminished, augmented, 7th, and extended chords for guitar, piano, and music theory.
Music chord intervals and notes are determined by counting semitones (half steps) from a root note on the chromatic scale. A chord is any combination of three or more notes played simultaneously. Understanding the interval structure of different chord types lets you build any chord from any root note.
Semitone counting formula: Note = Root + Interval (semitones)
The 12 chromatic notes (one octave): C, C#/Db, D, D#/Eb, E, F, F#/Gb, G, G#/Ab, A, A#/Bb, B, (C)
Chord interval formulas (semitones from root):
| Chord Type | Intervals from Root |
|---|---|
| Major triad | 0 - 4 - 7 |
| Minor triad | 0 - 3 - 7 |
| Diminished | 0 - 3 - 6 |
| Augmented | 0 - 4 - 8 |
| Major 7th | 0 - 4 - 7 - 11 |
| Dominant 7th | 0 - 4 - 7 - 10 |
| Minor 7th | 0 - 3 - 7 - 10 |
| Major 9th | 0 - 4 - 7 - 11 - 14 |
| Sus2 | 0 - 2 - 7 |
| Sus4 | 0 - 5 - 7 |
Interval names:
- 1 semitone = minor 2nd; 2 = major 2nd; 3 = minor 3rd; 4 = major 3rd
- 5 = perfect 4th; 6 = tritone; 7 = perfect 5th; 8 = minor 6th
- 9 = major 6th; 10 = minor 7th; 11 = major 7th; 12 = octave
Worked example: Build an F major 7th chord (Fmaj7):
- Root (0): F
- Major 3rd (+4): F → F# → G → G# → A
- Perfect 5th (+7): F → … → C
- Major 7th (+11): F → … → E
Fmaj7 = F, A, C, E
Now build Dm7 (D minor 7th):
- Root: D
- Minor 3rd (+3): F
- Perfect 5th (+7): A
- Minor 7th (+10): C
Dm7 = D, F, A, C — the same notes as Fmaj7 in a different order (inversion). This relationship is why ii–V–I progressions sound so smooth: the chords share common tones.