Hectopascals to newtons per square millimeter converter on this page calculates how many newtons per square millimeter are in 'X' hectopascals (where 'X' is the number of hectopascals to convert to newtons per square millimeter). In order to convert a value from hectopascals to newtons per square millimeter (from hPa to N/mm²) simply type the number of hPa to be converted to N/mm² and then click on the 'convert' button.