What you can do here
Read 29 individually written chord lessons, browse a 120-chord reference, identify chords from their notes, and listen to inversions. You can also try all 88 piano keys on a virtual instrument, practise common progressions, explore major and minor scales, use a metronome and print a 16-chord reference sheet.
The tools are free to use. The main piano practice and recording functions run inside your browser; you do not need an account or a music subscription.
How the chord information is made
Chord notes are built from pitch-class and interval rules in twelve-tone equal temperament. Our note-spelling code distinguishes C7 from Cmaj7 and keeps accidental spellings such as F♯ and B♭ visible. Original keyboard diagrams are generated from the chord data rather than copied from other sites.
Automated tests check important note spellings, voicings, page generation and interactions. These checks are useful, but they are not a substitute for a musician listening and reviewing every possible musical context.
Source, calculation and review boundaries
Our primary reference is the displayed chord-note data and the associated interval formulas. For example, C7 uses the major third E and minor seventh B♭; Cmaj7 keeps E but uses B natural. The keyboard illustrations and inversion note lists are generated from those same chord definitions, so the written labels and playable tones can be checked against each other.
Descriptions of mood and musical character are teaching language, not measurable acoustical facts. We have not published an independent music-teacher endorsement or a claim of professional accreditation. See the notation guide and seventh-chord comparison for worked examples.
How to check the theory
Our lesson notes come from the site's interval and diatonic-spelling engine rather than from generative text at playback time. For independent music-theory reading, see Open Music Theory's triad and seventh-chord reference. This is additional educational reading, not a claim that its authors reviewed or endorse this website.
What the diagrams do not prescribe
The illustrated keyboard is a reference voicing, not a required octave or a universal fingering. Your preferred hand shape can depend on range, nearby chords and physical comfort. Sound is browser-synthesized, not a recording of an acoustic piano.