Chord & Scale Explorer
Pick a key and a scale or mode. See the notes spelled correctly and every diatonic chord, then click anything to hear it. Share the URL to send someone the exact key you're working in.
Scale
Notes
Diatonic chords
Click a note or chord to hear it. Switch on 7th chords for richer, jazzier voicings.
What is a diatonic chord?
Every major or minor key contains seven notes. If you build a chord on each of those notes using only notes from the scale — stacking every other note — you get that key's diatonic chords. They're the chords that naturally sound "in key", which is why most songs are built almost entirely from them. The roman numerals (I, ii, iii, IV, V, vi, vii°) are a key-independent way to talk about those chords, so a "I–V–vi–IV" progression means the same shape in any key.
Scales, modes & how to use this
Choose a root and a scale or mode to see its notes spelled the way a musician would write them — C major reads C D E F G A B, never with a doubled letter. The seven church modes (Ionian through Locrian), plus harmonic and melodic minor, are all here. Flip on 7th chords to reveal the major-7, dominant-7, minor-7 and half-diminished colours that give a progression its mood. Found a key you like? The page URL updates as you go, so you can bookmark or share it. Need the exact pitch of a note? The Note & Frequency Calculator gives every note's frequency in Hz.