GuitarTheory
An interactive music theory tool designed for guitarists — from total beginners to seasoned players.
What is GuitarTheory?
GuitarTheory is an application that makes music theory approachable and visual. At its core is an interactive Circle of Fifths — a fundamental map of musical relationships that musicians have relied on for centuries. Instead of reading about it in a textbook, you can explore it directly: click any key, hear how it sounds, and instantly see how it connects to other keys, chords, and scales.
The app also includes a chord diagram library, a scale visualizer, a chord progression builder, and a music theory game — all designed to help you understand the relationships between notes, not just memorize them.
Who is it for?
🎸 Beginner guitarists
If you know a few chords but want to understand why they sound good together, GuitarTheory gives you the visual context to make sense of it all.
🎵 Intermediate players
Explore modes, build your own chord progressions, and start to see the patterns that tie scales and chords together across the fretboard.
🎼 Music students
Use the Circle of Fifths as a study tool for understanding key signatures, chord families, and harmonic relationships — visually and interactively.
🎶 Curious musicians
Even if you don't play guitar, the theory tools here apply to any instrument. Music theory is universal — this just happens to speak guitar.
What's inside
- ◈Circle of Fifths — Explore all 12 major and 12 minor keys with audio playback and related key highlighting. Choose your guitar sound — acoustic steel, electric jazz, distortion, or overdriven — from your profile.
- ◈Chord Visualizer — Browse 14 chord types across all 12 keys with fingering diagrams, interval degrees, staff notation, and compatible scales. Select notes you're playing and instantly identify what chord they form — or discover extended chords that contain those same notes.
- ◈Scale Visualizer — See scale patterns across the neck for a broad and growing library: church modes, pentatonics, blues, jazz scales, and exotic scales from world music traditions. Supports standard and alternate tunings — DADGAD, Open G, Drop D, and more — with patterns, notation, and TAB all updating together. Save your favorites for quick reference anytime — with more scales added all the time.
- ◈Chord Progression Builder — Build, play, and experiment with chord progressions. Share them or save them to your account.
- ◈GT Game — Test your ear and theory knowledge with an interactive game that adapts to your level.
- ◈Song Lab — Bring a chord progression, identify the key, and write guitar tablature all in one workspace. Includes live VexFlow notation, key analysis, style-specific lick and scale ideas, and a personal lick library — save and reuse your own tab phrases, share them with the community, and insert them anywhere in your tab with one click.
Our philosophy
Music theory has a reputation for being dry, abstract, and hard to apply. But it doesn't have to be. The goal of GuitarTheory is simple: help guitarists understand music, not just follow tab sheets or memorize patterns.
When you understand why a chord progression sounds the way it does, or why a particular scale fits over a certain key, you stop being a player who follows instructions and start being a musician who makes choices. That's what this tool is built for.
Get in touch
Have a question, a suggestion, or found a bug? We'd love to hear from you. GuitarTheory is actively being developed and your feedback shapes what gets built next.
rweeks@guitartheory.com