Chord-Scale Explorer

Select a chord type to see which scales fit and when to use each one.

What is Chord-Scale Theory?
A practical framework for choosing scales over chords

Chord-scale theory maps each chord type to one or more scales that sound consonant over it. Rather than memorizing arbitrary note choices, you learn which scales "fit" each chord and choose based on the musical context.

The idea is simple: every chord implies a set of tensions and extensions. A scale that contains the chord tones plus complementary extensions will sound coherent when played over that chord. Different scale choices add different colors and levels of tension.

For example, a dominant 7th chord (like G7) can take several scales depending on context. Mixolydian gives a basic, unaltered sound. The Altered scale provides maximum tension. Lydian Dominant offers brightness. The choice depends on what comes before and after the chord, the style of music, and the mood you want.

Select a chord type above to explore its scale options.

Explore further

Scales

Browse all the scales you can play over chords, with notes and fretboard diagrams.

Modes & Families

Deep-dive into each mode's character, chord fit, and guitar applications.

Chord Progressions

Apply chord-scale knowledge to real progressions, from ii-V-I to modal vamps.

Play Along

Test your scale choices over a real backing track and chord changes.

Common questions

What scale fits over a Cmaj7 chord?
C Ionian is the default. C Lydian (Ionian with a raised 4th) works when the chord is functioning as the I in a Lydian context, common in modern jazz and film scoring. Both contain the chord tones C-E-G-B; Lydian adds an F♯ that gives it a brighter, more open sound.
What's a chord-scale relationship?
Every chord has a set of scales that share its chord tones and add color tones around them. Improvising over a chord means picking a scale whose notes work: Dorian fits m7, Mixolydian fits dom7, altered fits dom7alt, and so on. The Chord-Scale Explorer maps every common chord to its compatible scales so you don't have to memorize the lookup table.
How do I find substitute chords?
Two common substitutions: tritone subs (replace a dom7 with the dom7 a tritone away, G7 becomes D♭7), and relative-quality subs (swap a chord for one sharing 3 of its 4 tones, Cmaj7 with Am7). The explorer shows compatible substitutes for each chord type so you can rewrite progressions without losing harmonic direction.