Theory Warrior character art

Theory Warrior

What the notes are, how chords are built, and why progressions work — music theory from first principles, no instrument required.

Chord Construction The Circle of Fifths Harmony Guides Transposer

Free reference pages for every note, interval, scale, mode, key, chord quality, and famous progression — each stated as a formula in plain note names, so the same fact holds on any instrument you pick up.

Start Here

Theory has a reputation for gatekeeping that it doesn't deserve. Everything on this site is stated in note names, distances, and formulas — no notation required — and every fact is generated from one tested data layer, so the tables are never wrong in a corner somewhere. Pick the door that matches where you're standing:

The Ground-Up Path

Completely new? Start with the twelve notes, then the distances between them, then the patterns those distances make. Notes → intervals → scales → keys: four short sections, in order, and the whole system stands up in front of you.

The Why-It-Works Path

Already play, but want the why? You know the chords; nobody ever explained what they're doing. The harmony guides start there — why V pulls home, why phrases end the way they do — and every claim links back to the chords and keys you already use.

The Songwriter's Path

Writing songs? Steal like a professional: the famous progressions, explained and written out in every key — then the moves that make them yours: substitution, borrowed chords, and the key change that lifts a final chorus.

Every Section

Notes

The twelve notes: frequencies, MIDI numbers, enharmonics, and the triads and keys built on each.

12 notes

Intervals

Every distance between notes — ratios, cents, characters, and the songs that teach your ear each one.

13 intervals

Scales

Twenty-four scale types with interval formulas, degrees, and the notes of every scale in every key.

24 scales

Modes

The seven modes of the major scale — what makes Dorian roll and Lydian float, with diatonic harmony.

7 modes

Keys

All twenty-four major and minor keys: diatonic chords with Roman numerals, relatives, and parallels.

24 keys

Chords

Chord construction from first principles: 62 chord types on any root, formula by formula.

62 types × 12 roots

Progressions

The famous chord progressions — why they work, who used them, and how they sound in every key.

Named patterns

Circle of Fifths

The interactive key map: signatures, relative minors, and diatonic chords around the circle.

Interactive

Harmony

How chords work together: function, cadences, and voice motion — the guides that tie it all together.

Guides

Tools

Transposer, interval calculator, scale finder, and a theme builder — instant, in-browser utilities.

4 tools

How It Works

1

Pick a Concept

Start anywhere — a note, a distance, a chord symbol a chart keeps throwing at you. Every page defines its object in plain language before doing anything else with it.

2

Read the Formula

Each entry states its recipe in note names and semitone distances, then spells it out in whatever key you choose — the same register everywhere, notation never required.

3

Follow the Connections

Intervals stack into chords, scales settle into keys, keys map onto the circle — every page links up and down that chain, so one lookup becomes a working understanding.

The Instrument-Neutral Home

Theory Warrior is the Warrior Network's answer to "what is this, actually?" — the one site in the family with no strings, frets, or fingerings anywhere in its prose. The premise: a chord, a key, or a mode is the same object no matter what plays it, so its definition deserves a page that any musician can use. Every table here is generated from the network's shared, CI-tested theory data — the same layer the instrument sites voice their diagrams from — and when you want to hear an idea under your fingers, the play-it panels door out to those sister sites rather than pretending this one owns a neck.

The Questions Theory Learners Ask

The full FAQ has the longer list.

Do I need an instrument to use this site?
No. Every fact is stated in note names, semitone distances, and formulas, which are true on any instrument and on none. When you do want to hear a concept under your fingers, the pages door out to the network's instrument sites for playable versions.
Is music theory a set of rules I'll be breaking?
Theory here is treated as description, not law: names for things your ear already responds to. The pages explain why the common patterns work — and when a page documents a convention rather than a necessity, it says so plainly.
How much math is involved?
Counting to twelve. Intervals are measured in half steps, scales are patterns of steps, and chords are stacks of intervals — arithmetic, not algebra. Frequency ratios and cents appear where they explain something, and are always optional reading.
Can I trust the tables?
Every spelled scale, diatonic chord row, and chord formula is generated from one shared, continuously tested data layer — the same one the network's instrument sites voice their diagrams from — so a printed table cannot quietly drift from the underlying data.
What does Theory Warrior cost?
Nothing. All reference sections, harmony guides, and tools are free, with no ads and no account; preferences like your color theme stay in your own browser.