OtoTheory — Use Theory Without Tears
A music theory-powered composition tool for guitarists.
Learn theory while you create.
Understand chords, progressions, keys, and scales visually,
without struggling through dense theory books.
What is OtoTheory?
OtoTheory is a practical music theory tool designed specifically for guitarists.
Use it when you want to:
- Learn your first chord progressions
- Compose original songs
- Find out which chords work together
- Discover which notes to use for melodies and solos
OtoTheory provides instant answers with interactive guitar fretboards, automatic chord suggestions, and smart capo recommendations.
No music theory degree required.
Just bring your curiosity and your guitar.
Key Features
🎸 Find Chords from Key & Scale
Enter any key and scale to instantly see which chords work together. Visualized on guitar fretboard with both open and barre forms.
🎵 Build Chord Progressions
Create and listen to progressions with automatic playback. Choose from 20+ preset patterns (Free) or 50+ with Pro.
🎯 Capo Suggestions
Get smart capo recommendations that make difficult keys easier to play. See both "Shaped" (what you finger) and "Sounding" (what you hear) notation.
🎨 Visual Fretboard Overlay
Two-layer display shows scales (outline) and chords (filled) simultaneously. Toggle between note names and scale degrees.
📤 Export & Share
Export progressions as PNG images (Free) or MIDI files with chord tracks, section markers, and guide tones (Pro).
Who is it for?
📚 Beginners
Learn which chords belong together without memorizing theory books.
✍️ Songwriters & Composers
Experiment with progressions quickly and discover fresh chord combinations. Visualize which notes match your chords for better melodies and solos.
🎓 Self-learners
Understand practical theory concepts through interactive visualization.
🎸 Guitarists of All Levels
Get instant answers to "What chord comes next?" and "Which notes should I use for my solo?"
Our Philosophy
Music theory should be a tool, not a barrier.
We believe that understanding keys, scales, and chord progressions shouldn't require years of formal training.
OtoTheory was created to bridge the gap between "I want to create music" and "I don't know where to start."
Our goal is simple:
Help you make music with confidence, whether you're writing your first song or your hundredth.
Free vs Pro
🆓 Free (Web & iOS)
- • Find chords from any key/scale
- • Build progressions (up to 12 chords)
- • 20 preset patterns
- • PNG export
- • 3 saved sketches (local)
💎 Pro (iOS, ¥490/month)
- • 50 preset patterns
- • Section editing (Verse/Chorus/Bridge)
- • MIDI export with chord tracks & markers
- • Unlimited cloud-saved sketches
- • 7-day free trial
Ready to explore?
Free, no signup required for web version