Music Theory
Trainer

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Studies for the daily practice
— Today's training · #050 —

Etudle

Three rounds, fifteen flashcards, one shot per day. Same training worldwide — race the clock and build your streak.
2026-06-14 · 3 rounds · 15 cards
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rounds
— Practice gauntlet —
Run the gauntlet
Five-card rounds drilling one focused topic at a time — chord, interval, note, or key. New round each time.
Just starting1 more round
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— Opus I —
Chord Trainer
Triads and extended chords across every root — major, minor, diminished, augmented, plus optional 7ths, 9ths, and 13ths. Spell the chord on a staff or by typing, or name it from its notes.
I. Chord → notes
II. Notes → chord
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— Opus II —
Circle of Fifths
Every key signature around the circle, major and minor. Mark the sharps and flats, or read the scale and name the key.
I. Key → sharps & flats
II. Scale → name the key
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— Opus III —
Interval Trainer
2nds through 7ths plus the 4th, tritone, and 5th. Toggle which intervals to study, then name the note that lies above each root.
I. Toggle any subset
II. Root + interval → note
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— Opus IV —
Note Trainer
A single note shown on a music staff, piano keyboard, or guitar fretboard. Identify the letter and accidental — fret position and octave randomise per card.
I. Choose your displays
II. Display → name the note
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What is Music Theory Trainer?

Music Theory Trainer is a free, ad-free flashcard tool for the fundamentals of Western music theory: chords, scales, key signatures, intervals, and note reading. Every concept is drilled with interactive practice — not lectures, not videos, not lessons — because fluency in theory comes from spaced repetition, the way fluency in a language comes from speaking it.

Why flashcards for music theory?

The hard part of music theory isn't understanding the rules; it's recalling them fast enough to use them. When you're sight-reading on stage, transcribing a piece, or analyzing a chord progression on the fly, you don't have time to think "the third of D major is F♯ because the major-third interval is two whole steps…" — you need that information to be reflexive. Flashcards build reflexes. Spaced repetition is the most-studied method for memorizing factual content, and music theory is full of factual content (key signatures, chord spellings, intervals) waiting to become automatic.

What you can drill

  • Chord Trainer — every major, minor, diminished, and augmented chord, plus 6ths, 7ths, 9ths, 11ths, 13ths, and add chords across all 12 roots. Two directions (spell the chord from a name, or name the chord from its notes) and four input modes (tap, music staff, piano keyboard, guitar fretboard with real-world fingerings).
  • Circle of Fifths Trainer — all 14 major and 14 minor key signatures. Mark sharps and flats from a key name, identify keys from their scales, or drill relative minors.
  • Interval Trainer — minor 2nds through major 7ths plus the perfect 4th, tritone, and perfect 5th. Both directions (find the note above a root, or find the root below a note).
  • Note Trainer — identify single notes on the music staff, piano keyboard, or guitar fretboard. Both directions (see a note, name it; or hear a name, place it).
  • Etudle — a 15-card daily music theory puzzle with a global leaderboard. Same puzzle worldwide, refreshing at midnight UTC. Like Wordle, but for chords, keys, and intervals.
  • Practice Gauntlet — no-setup mode that drops you into focused 5-card rounds picked at random across all the trainers. Tier ranks (Apprentice → Maestro) reward sustained practice.

How this is different

Most reference sites for music theory have great explanations but no practice tool. Most practice tools are old-school and don't scale to phones. Music Theory Trainer is built for both — interactive flashcards for every chord, key, scale, and interval referenced on the site, with mobile-first input modes that don't require a physical keyboard.

It's free, requires no account, runs in your browser, and tracks your best times in your own browser storage. The Etudle leaderboard is the only thing that touches a server, and it's anonymous by default. There are no ads, no email collection, no tracking pixels — just the practice tool and the words to explain it.

Who is this for?

Self-taught musicians who want to drill the fundamentals to fluency. Music students working on theory homework, ear training, or sight-reading. Guitarists who never properly learned to read sheet music and want to. Pianists studying jazz harmony. Anyone who's tried to memorize the circle of fifths from a diagram and wished there was a faster path. The trainers are designed for self-directed practice, but the daily Etudle puzzle and Practice Gauntlet make it social and game-like for casual players too.

Created by Pierce Porterfield