Question: how do you convert 1 km to mm?
Answer: Kilometers to Millimeters Conversion There are 1000000 millimeters in a kilometer. To convert kilometers to millimeters, multiply the kilometer value by 1000000. For example, to find out how many millimeters in a kilometer and a half, multiply 1.5 by 1000000, that makes 1500000 millimeters in a kilometer and a half.