Music Theory on the Fretboard
Understand the logic behind the music you play and how it maps onto the guitar. Learn how notes, chords, keys, and scales connect so you can improvise, write songs, and jam with confidence.
Like Duolingo, but for Music Theory on the Fretboard. Tomo turns the whole topic into a game you play five minutes a day, until it actually sticks.
25 levels across 3 sections, about 50 minutes end to end, roughly 10 days at five minutes a day. It moves through Finding Your Way on the Fretboard; How Chords and Keys Fit Together; and Scales, Solos, and Melodic Expression. It starts from scratch.
Free forever · No credit card · iPhone & Android
Key ideas in Music Theory on the Fretboard
- The musical alphabet consists of only seven letters: A, B, C, D, E, F, and G
- After reaching G, the sequence immediately wraps around to A at a higher pitch rather than continuing with H
- Natural half steps occur exclusively between B-C and E-F, meaning they sit on adjacent frets with no fret between them
- All other adjacent natural letter pairs (such as A-B, C-D, D-E, F-G, G-A) sit two frets apart with an empty fret between them
- A sharp raises a note by one fret, while a flat lowers a note by one fret
- The space between G and A can be reached either by raising G one fret (G#) or lowering A one fret (Ab), producing the same sounding pitch
- Open strings act as fixed baseline pitches for counting up the musical alphabet
- Moving up from the open A string: fret 2 is B, and because B and C are a natural half step apart, fret 3 is C
- Octaves share identical note names at higher or lower pitch registers
- A standard octave shape on the lower guitar strings spans down two strings and up two frets (for example, from the 3rd fret G on the 6th string to the 5th fret G on the 4th string)
- An interval is the musical distance between two pitches rather than a specific pitch itself
- A melody is defined by the sequence of intervals between notes, allowing it to be transposed to start on any letter note without changing its identity
- Absolute letter names change when you shift keys, but relative distances stay the same
- Octaves, fifths, and fourths provide the most acoustically stable, open framework in Western harmony
- These stable intervals historically earned the label 'perfect' because of their clean, blending sound
- Thirds add warmth and specific mood rather than raw structural stability
You've tried the other tabs
Thirty open tabs. Four facts you actually kept.
You watched. You nodded. By Sunday it was gone.
One answer, then back to scrolling.
Eight weeks. You meant to finish. You didn't.
Tomo gives Music Theory on the Fretboard the Duolingo treatment: levels, streaks, and quick quizzes that test what you just learned. That game loop is what the tabs above never had, so it's the one you actually finish.
Here's what playing it feels like
A real question from this course. Take your best guess.
When you are going up in pitch and reach G, which letter comes next?
Get it right to open this lesson and 24 more in the app.
Where Music Theory on the Fretboard takes you
- 1
Finding Your Way on the Fretboard
- Finding Notes Across the Neck
- Intervals: The Building Blocks of Sound
- 2
How Chords and Keys Fit Together
- Building Triads and Basic Chords
- Keys, Numbers, and Chord Progressions
- Movable Shapes and the CAGED System
- 3
Scales, Solos, and Melodic Expression
- The Major Scale and Its Modes
- The Pentatonic Scale and Lead Playing
- Ear Training and Musical Phrasing
3 sections · 8 units · 25 levels. Built to play, not to enroll.
Tomo is in ChatGPT
Tomo is also a ChatGPT plugin: the same playable courses, built and played inside your chat.
Add Tomo to ChatGPT- What to ask
- “Make me a Tomo course on black holes.” “Turn this chat into a Tomo course.”
- What you get
- Quick questions with instant feedback, hearts and stars, ready to play in about a minute.
- Where it goes
- No sign-up to start. Connect your Tomo account and your streak carries on in the app.
You pick the voice
Music Theory on the Fretboard is taught in the Explain Like I'm 5 style: no big words. promise.. Want a different feel? In the app you can spin up the same topic in any of Tomo's teaching styles. Same facts, totally different vibe.
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How Melody and Harmony Work
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Start Music Theory on the Fretboard today.
Download Tomo, search Music Theory on the Fretboard, and play your first lesson in under a minute.