FIDE ratings are converted to US Chess ratings according to the following Formula
USCF = FIDE + 50 if FIDE >= 2200
USCF = 0.765 x FIDE + 560 if FIDE < 2200
For a US player US Chess ratings are usually used even if the player has a FIDE rating. For foreign players the highest of US Chess, FIDE or other national ratings is used. The Chief Tournament Director may use whichever rating he believes most accurately reflects the player’s true strength.
