Megapascals to newtons per square millimeter conversion calculator shown above calculates how many newtons per square millimeter are in 'X' megapascals (where 'X' is the number of megapascals to convert to newtons per square millimeter). In order to convert a value from megapascals to newtons per square millimeter (from MPa to N/mm²) simply type the number of MPa to be converted to N/mm² and then click on the 'convert' button.