Music theory
Music theory you can hear and play
Every chord and scale, spelled out, on the keyboard and ready to play. Look something up, hear it, then play it yourself. Free, no account needed.
- 144 chords
Piano chords
144 chords on 12 roots: major, minor, sevenths, sus and more. The notes, the inversions and the keys each chord belongs to.
Open - 120 scales
Scales
120 scales: major, minor, pentatonic, blues and the modes. The notes, the step pattern and the chords built from each one.
Open - 30 keys
Keys
All 30 major and minor keys on the circle of fifths: the key signature, the scale, every chord in the key and its closest neighbours.
Open - Interactive
Circle of fifths
An interactive circle of all 12 keys and their relative minors: tap a key for its key signature and neighbours, and play its scale.
Open - 8 progressions
Chord progressions
I–V–vi–IV, I–IV–V, ii–V–I, the 12-bar blues and more, in every key: hear each one and play it chord by chord.
Open - 4 pages
Rhythm
Note values, rests, dotted notes and time signatures, with rhythms you can hear and tap along to.
Open - 12 intervals
Intervals
All twelve intervals from the minor second to the octave: how many half steps, how they sound and a song to recognise each one by ear.
Open - 8 pages
Reading notes
The staff, the treble, bass, alto and tenor clefs, middle C and ledger lines, with a quiz that has you play every note you read.
Open - Blog
Short reads
One idea per article, written so you can go and play it straight away.
Open
Where to start
New to theory? These pages cover the foundations most songs are built on.
Go from looking it up to knowing it
PlayTheory's lessons take you from the twelve notes to chords, keys and progressions, one step at a time, and every step waits for you to play it.
Start free