Atmospheres (standard) to megapascals conversion calculator above calculates how many megapascals are in 'X' atmospheres (standard) (where 'X' is the number of atmospheres (standard) to convert to megapascals). In order to convert a value from atmospheres (standard) to megapascals (from atm to MPa) simply type the number of atm to be converted to MPa and then click on the 'convert' button.