These are the difficulties from Hinson.
Mozart's piano sonatas
Easy, Intermediate (Int.), Moderately Difficult (M-D), and
Difficult (D).
K279 - M-D
280 - M-D
281 - M-D
282 - M-D
283 - M-D
284 - M-D to D
309 - M-D
310 - M-D
311 - M-D
330 - M-D
331 - M-D
333 - M-D
457 - D
494/533 - D
545 - M-D
547a - M-D
570 - M-D
576 - D