Open Key

Open Key is the other short notation for keys. It uses numbers from 1 to 12 with the letters m and d — minor and major, in the convention Traktor popularised — where Camelot uses A and B.

Both describe exactly the same circle of fifths; the only difference is where the numbering starts. That makes conversion between them a fixed offset, and it is why an off-by-one is so easy: copy a table from one place, compare it against another, and a single position out of step goes unnoticed until two tracks that should have fitted sound wrong.

Which one you use depends on your software more than on taste. Traktor leans Open Key; Rekordbox and Mixed In Key lean Camelot. If you work with libraries that came from both worlds, you will see both notations in the same folder.

Our equivalence table shows all three forms — musical notation, Camelot and Open Key — on the same row, so conversion is something you read rather than something you calculate. It is also exactly the kind of table worth checking against your own before trusting a set to it: not all of the ones in circulation are correct.