Millimeters per second to kilometers per hour conversion calculator above calculates how many kilometers per hour are in 'X' millimeters per second (where 'X' is the number of millimeters per second to convert to kilometers per hour). In order to convert a value from millimeters per second to kilometers per hour (from mm/s to km/h) simply type the number of mm/s to be converted to km/h and then click on the 'convert' button.