Latitude and longitude are imaginary lines that form a grid on the earth's surface. For centuries, these lines have been indispensable navigational aids for sailors and others who need to plot their exact position on the globe. Because earth is approximately spherical, you can easily calculate the distance between any latitude lines. However, if you are simply planning a trip or a hike, you may find it more helpful to know the number of kilometers (or miles) you will be covering, rather than the exact number of degrees of latitude.

Find the circumference of the earth. Traveling all the way around the world by the longest north-south route, you would cross 180 degrees of latitude on the first half of your trip and 180 degrees on the second half. This journey would cover approximately 40,700 km and 360 degrees of latitude.

Divide earth's circumference (40,700 km) by 360 to find the distance each latitude degree covers. This works out to roughly 113 km per degree of latitude.

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Subtract the latitude with the lower numerical value from the latitude with the higher numerical value (for example, if you are traveling from 45 degrees north to 48 degrees north, subtract 45 from 48). If your journey will take you across the equator, use negative numbers to represent latitudes in the southern hemisphere (for example, if you are traveling from 2 degrees south to 1 degree north, subtract -2 from 1, giving you a total of 3).

Multiply the difference between your origin and destination latitudes by 113 to calculate the distance between these lines in kilometers. If you prefer to know the distance in miles, divide your result by 1.6.

#### Tip

To calculate distance more accurately, you can further divide degrees of latitude into minutes and seconds. Each degree contains 60 minutes, while each minute contains 60 seconds. Simply divide by 60 the distance a degree covers to find the distance a minute covers, and divide by 60 again to find the distance a second covers.

#### Warning

It is unusual for roads or trails to travel due north or south, so this calculation will give you only the approximate distance you will be traveling, even if you calculate to the minute or second.