Kilometers per hour to nautical miles per day conversion calculator shown above calculates how many nautical miles per day are in 'X' kilometers per hour (where 'X' is the number of kilometers per hour to convert to nautical miles per day). In order to convert a value from kilometers per hour to nautical miles per day (from km/h to nmi/d) simply type the number of km/h to be converted to nmi/d and then click on the 'convert' button.