Calculating the distance between two cities in miles can be an extremely useful skill. Drivers, hikers and bikers all rely on accurate distance calculations when planning trips. It's important to communicate approximate locations when hiking for safety reasons. Drivers want to be able to calculate gas mileage and potential rest stop locations. Bikers may want to determine break locations as well. Calculate the distance between two cities in miles using a calculator and a map's key or modern technology to have the safest and most efficient trip possible.

### Things You'll Need

- Map
- Ruler
- String

- Calculator
- GPS device (optional)

Figure out where you want to go. You should have the names and approximate locations of your starting point and destination. Be sure to get as close as possible, for example, Thornton (a suburb of Denver) is more specific than just Denver. Identify these locations on a printed or web-based map.

Identify the map key, and calculate the distance using a ruler and the key provided. For example, the distance may physically be 2 inches on the map, but the key may reveal that 1 inch on a map equals 400 miles. Therefore, you'll need to make the conversion that you'll be traveling 800 miles.

Use the calculator to check your calculations and get as close an approximation as you can. For example, it's rare that you will have a distance of exactly 2 inches between the cities you want to go to. You'll need to factor in winding roads that may add to the total distance between cities. Using a piece of string to measure the windy road and then straightening it out along the length of a ruler is one way to overcome this obstacle.

Enter your data into an online mapping website or check the total distance online using a trip calculator. These are tools most travelers use today as they calculate distances between cities by using satellite data. If you have an older map, an online trip calculator may be the solution for you to verify the distance you calculated. Web-based trip calculators are more accurate than many cartographers who created maps in the past.

Check your data using a GPS device if possible. A GPS unit will help you determine where you need to go in relation to where you are. Some GPS devices can get as close to where you want to go as a few feet.