Major
1–3–5
Major third + perfect fifth.
Chord construction
Build any chord from intervals instead of memorizing names.
Chord symbols become much easier when you can translate them into interval formulas. Start with triads, then add sevenths and extensions.
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Triads
Three notes define the basic quality.
Start with root, third and fifth.
Minor
1–b3–5
Lower the third.
Diminished
1–b3–b5
Lower third and fifth.
Augmented
1–3–#5
Raise the fifth.
Seventh chords
Add one more chord tone.
The seventh creates new color and function.
Maj7
1–3–5–7
Major seventh.
7
1–3–5–b7
Dominant seventh.
m7
1–b3–5–b7
Minor seventh.
m7b5
1–b3–b5–b7
Half-diminished.
Extensions
Continue stacking scale degrees.
9ths, 11ths and 13ths extend the seventh-chord structure.
9
Add scale degree 2
Above the octave.
11
Add scale degree 4
Context-sensitive against major 3rd.
13
Add scale degree 6
Common dominant extension.
FAQ
Quick answers about chord construction.
Use these answers as a reference, then explore the relationships interactively.
How are chords built?
Chords are built by combining intervals above a root, commonly thirds that create triads, seventh chords and extensions.
What is a chord formula?
A shorthand interval description such as 1–3–5 for major or 1–b3–5 for minor.
Do chord formulas change with key?
No. The interval formula stays the same; only the note names change with the root.
ChordRevelation
Move from explanation to interactive harmony.
Change the key, compare voicings, follow voice leading and see the same idea directly on the fretboard.