Miles to Kilometers Converter

kilometers = miles x 1.609344. The factor follows from the inch: a mile is 63,360 inches, an inch is 25.4 millimeters, and the two together give 1,609,344 millimeters to the mile.

How many kilometers is a 5K, 10K and a marathon in miles?

A 5K is 3.107 miles, a 10K is 6.214 miles, a half marathon is 13.109 miles and a marathon is 26.219 miles. Race distances are set in kilometers, which is why the mile figures are never round numbers.

How do I convert a speed limit in my head?

Take off a third and add a little. 100 km/h is about 62 mph; 50 km/h is about 31 mph. The other direction: 60 mph is close to 100 km/h, which is the pairing worth memorizing.

Why is the factor 1.609344 and not 1.6?

Because 1.6 is rounded. It is fine for a rough estimate, but it is off by about half a percent, which over a marathon is more than 200 meters - roughly the difference between a personal best and a story about a personal best.