Converting Miles to Kilometers (mi to Km) Example Problem

Worked Length Unit Conversion Example Problem

2009 Ford Focus speedometer
Speedometer is numbered in increments of 20, which makes it difficult to tell your speed at a glance when you're driving 65 to 75. Photo © Aaron Gold

The method to convert miles to kilometers is demonstrated in this worked example problem. A mile (mi) is a unit of distance used in the United States, particularly for travel. The rest of the world uses kilometers (km).

Miles to Kilometers Problem

The distance between New York City, New York, and Los Angeles, California is 2445 miles. What is this distance in kilometers?


Start out with the conversion factor between miles and kilometers:

1 mile = 1.609 km

Set up the conversion so that the desired unit will be canceled out. In this case, we want kilometers to be the remaining unit.
distance in km = (distance in mi) x (1.609 km/1 mi)
distance in km = (2445) x (1.609 km/1 mi)
distance in km = 3934 km


The distance between New York City, New York, and Los Angeles, California is 3934 kilometers.

Be sure to check your answer. When you convert from miles to kilometers, your answer in kilometers will be about one and a half times larger than the original value in miles. You don't need a calculator to see whether or not your answer makes sense. Just make sure it's a larger value, but not so big that it's twice the original number,

Kilometer to Miles Conversion

When you work the conversion the other way -- from kilometers to miles -- the answer in miles is a bit more than half the original value.

A runner decides to run a 10k race. How many miles is it?

To solve the problem, you can use the same conversion factor or you can use the conversion:

1 km = 0.62 mi

This is easier because the units cancel out (basically just multiply a distance in km times 0.62).

distance in miles = 10 km x 0.62 mi/km

distance in miles = 6.2 miles