Find the mileage scale on the map. The mileage scale is usually printed in one of the corners of the map. The scale is a line broken into segments. Each segment represents a distance in miles.
Measure the scale line with a ruler. Note how long the line is. Most scales are only a couple of inches long. The distance represented by an inch will depend on the size of the map and the size of the page.
Take the ruler and place it on the road being measured. If the road is a straight line, note how many inches are between the points being measured. If the road is not a straight line, draw small marks along the road at intervals that correspond to the length of the scale. For example, if the scale is an inch long, mark dots at 1 inch intervals. Then count the intervals marked.
Add the number of scale lengths used between intervals. If the scale is 1 inch long and the road is 6 inches long then write down the number 6.
Multiply the length number determined above by the number of miles in the scale. If the scale on the map indicates that there are 40 miles per inch and the road is 6 inches long, multiply 40 by 6. The result will be the trip's distance in miles.
