The Chord Calculator & Finder works in both directions. In Build mode, choose a root note and a chord type, from basic triads and 7ths to 9ths, 13ths, altered dominants and added-note chords, and see the notes, the interval formula, every inversion on a piano keyboard, and hear the chord or its arpeggio. In Find mode, tap the keys you are holding or type the notes, and the tool names the chord, flags inversions by the bass note, and lists every close match with what is missing or extra.
It is a quick way to check a chord you are reading, to name something you found by ear on the piano, or to learn how extended chords are built one interval at a time.