# Music Theory Center

> A free music theory course and reference. 19 chapters in five parts, from first principles to advanced harmony, plus a playable page for every interval, chord, scale and progression. No account, no paid tier.

Everything sounds: examples play through a persistent dock that draws the reader's own instrument — piano, guitar, bass or ukulele — on every page. The interface, the course and all 101 reference articles are written in English, French and Spanish.

## How the course is built

- You hear it before it has a name. Every section opens with a sound and a question, not a definition; the term arrives third. Any note, chord or interval named mid-sentence is a button that plays it.
- No instrument is the default. Chapters draw no instrument of their own — you pick piano, guitar, bass or ukulele once, and every example on the site is redrawn on it.
- Reading music is optional. Notation is chapter 4, and it is a prerequisite of no other chapter.
- Ear training is part of the course, not a separate app. It starts at chapter 6, and from there every chapter has something to identify by ear.
- A wrong answer explains itself. Every option in every check carries its own explanation: what you probably heard, what it was, and the difference. Retrying is unlimited.
- No score, no streak, no account, no subscription. The only thing stored is which chapters you have opened, in your own browser.
- Claims are typed. Every statement is marked as a fact, a naming convention, a stylistic tendency or a written constraint — and tendencies and constraints always state whose music they describe.

## Course

[All chapters](https://musictheory.center/course)

### Sound

- [1. Fundamentals of Music Theory](https://musictheory.center/course/fundamentals) — 4 sections, Beginner
- [2. Pitch, Notes and the Octave](https://musictheory.center/course/pitch-and-notes) — 6 sections, Beginner
- [3. Rhythm, Beat and Tempo](https://musictheory.center/course/rhythm) — 5 sections, Beginner
- [4. Reading Music: The Staff](https://musictheory.center/course/notation) — 6 sections, Beginner

### Materials

- [5. Intervals](https://musictheory.center/course/intervals) — 6 sections, Beginner
- [6. Training Your Ear](https://musictheory.center/course/ear-training) — 5 sections, Beginner
- [7. Scales: Major and Minor](https://musictheory.center/course/scales) — 6 sections, Beginner
- [8. Keys and Key Signatures](https://musictheory.center/course/keys-and-key-signatures) — 6 sections, Intermediate
- [9. Modes](https://musictheory.center/course/modes) — 6 sections, Intermediate

### Harmony

- [10. Chords: Triads and Sevenths](https://musictheory.center/course/chords) — 6 sections, Intermediate
- [11. Diatonic Harmony](https://musictheory.center/course/diatonic-harmony) — 6 sections, Intermediate
- [12. Voice Leading](https://musictheory.center/course/voice-leading) — 5 sections, Intermediate
- [13. Melody: Motif, Phrase and Line](https://musictheory.center/course/melody) — 6 sections, Intermediate
- [14. Chromatic Harmony](https://musictheory.center/course/advanced-harmony) — 6 sections, Advanced

### Shape

- [15. Meter, Syncopation and Groove](https://musictheory.center/course/meter-and-groove) — 6 sections, Intermediate
- [16. Form and Structure](https://musictheory.center/course/form-structure) — 5 sections, Intermediate

### Applied

- [17. Theory in Styles](https://musictheory.center/course/contemporary) — 5 sections, Intermediate
- [18. Arranging and Instrumentation](https://musictheory.center/course/orchestration) — 6 sections, Advanced
- [19. Putting It Together](https://musictheory.center/course/applications) — 5 sections, Advanced

## Reference

- [Intervals](https://musictheory.center/intervals) — The distance between two notes — the unit every scale and chord is built from.
- [Music chords](https://musictheory.center/chords) — Every chord type, from triads to altered jazz voicings: what it is, how it is built and how it sounds. Each one is playable on any of the twelve roots, on piano, guitar, bass or ukulele.
- [Musical scales](https://musictheory.center/scales) — Every scale and mode, from the major scale to the altered scale: the notes, the pattern of tones and semitones, and what it is used for. Each one is playable on any of the twelve tonics.
- [Chord progressions](https://musictheory.center/progressions) — The sequences songs are actually built from, written in roman numerals so they work in any key.

## Tools

Free tools that do something with theory rather than explain it: find a key, name a chord, transpose a progression. Every result can be played.

[Music Theory Tools](https://musictheory.center/tools)

- [Chord transposer](https://musictheory.center/tools/chord-transposer) — Paste a progression in any key and read it back in another, as chord symbols or roman numerals, and hear it on your instrument.
- [Roman numeral converter](https://musictheory.center/tools/roman-numeral-converter) — Type chords and read them as roman numerals, or type numerals and read them as chords in any key.
- [Key finder](https://musictheory.center/tools/key-finder) — Enter the chords of a song and see which keys they fit, which chord is doing what, and where the borrowed ones come from.
- [Chord identifier](https://musictheory.center/tools/chord-identifier) — Play or type a handful of notes and get the chord they spell, its inversions, and the other names it goes by.
- [Scale finder](https://musictheory.center/tools/scale-finder) — Pick the notes of a melody or riff and find every scale that contains them, from the major scale to the modes and beyond.
- [Interval calculator](https://musictheory.center/tools/interval-calculator) — Two notes in, an interval out — or a note and an interval in, and the note that lands. With the sound of it, both ways.
- [Interactive circle of fifths](https://musictheory.center/tools/circle-of-fifths) — Turn the circle to any key and read off its scale, its diatonic chords, its neighbours and its relative minor.

## Lessons

Self-contained explanations of one idea each, outside the course sequence.

- [Is Music Theory Still Worth Learning Now That AI Can Write Songs?](https://musictheory.center/lessons/music-theory-and-ai)
- [Understanding Musical Notes](https://musictheory.center/lessons/musical-notes)
- [How to Read Sheet Music Fast: Proven Tricks for Beginners](https://musictheory.center/lessons/read-sheet-music-fast)
- [Why Understanding Scales Is the Key to Every Song You Play](https://musictheory.center/lessons/why-learn-scales)
- [Circle of Fifths Explained: A Visual Guide for Beginners](https://musictheory.center/lessons/circle-of-fifths)
- [Modes in Music Explained: How to Use Dorian, Lydian & Mixolydian](https://musictheory.center/lessons/modes-explained)
- [Negative Harmony](https://musictheory.center/lessons/negative-harmony)

## About

[How this course is built, and what it does not do](https://musictheory.center/about)

## Notes

- Prerequisites are listed on every chapter and are shown, never enforced. No chapter is locked.
- No time estimates are published anywhere; the portion signal is the section count.
- Real recordings are cited throughout the course, each with a note on where in the track to listen.

## Other formats

- [The complete course as one Markdown file](https://musictheory.center/llms-full.txt)
- Each chapter is also available as Markdown at its own URL plus /llms.txt — for example: https://musictheory.center/course/fundamentals/llms.txt

## Other languages

- https://musictheory.center/llms.txt
- https://musictheory.center/fr/llms.txt
- https://musictheory.center/es/llms.txt