Find the scale that the map uses. An example of a scale would be that an inch on the map equals 50 actual miles. In this case, 50 miles is the conversion factor.
Measure the distance between two points on the map using a ruler. Be sure to use a measuring device consistent with the map's scale; if the map uses inches as its scale, your ruler must as well.
Multiply the distance in inches measured on the map by the conversion factor. So, for example, if you measured 30 inches on the map and the scale states that every inch equals 50 miles, you must multiply 30 by 50 in order to arrive at the actual distance of 1,500 miles.
