Kilometers to miles, the short of it
One kilometer is 0.621371 miles. Roughly five eighths of a mile. That ratio comes from the mile being defined as exactly 1.609344 km, flipped around. Whenever a distance shows up in kilometers and you measure your world in miles, this bridges the gap.
Drop a value in and the miles appear as you type. The math happens locally in your browser, so nothing gets uploaded and there’s no server in the loop.
Running races make this click
If you run, you’ve hit this conversion. Race distances are stubbornly metric almost everywhere. A 5K is 3.107 miles. A 10K works out to 6.214 miles. The half marathon, technically 21.0975 km, is 13.109 miles, and a full marathon (42.195 km) is the famous 26.219 miles.
Pace gets interesting here. If you run 5 minutes per kilometer, that’s about 8:03 per mile, since a mile is longer. Mixing up the two is how people end up confused about whether they’re getting faster.
Driving and speed limits abroad
Rent a car in Europe and the dashboard reads kilometers, the signs read kilometers, but your sense of distance might not. A 100 km drive is 62.1 miles, comfortably over an hour on a highway. When a sign says the next town is 30 km away, that’s 18.6 miles.
Speed limits trip up visitors constantly. A 120 km/h motorway limit is 74.6 mph. A 50 km/h urban limit is 31.1 mph. Plug in the number on the sign and you’ll know whether you’re cruising or crawling by your usual gauge.
Handy distances:
- 1 km = 0.621371 mi
- 5 km = 3.10686 mi (a 5K race)
- 10 km = 6.21371 mi
- 42.195 km = 26.2188 mi (a marathon)
- 100 km = 62.1371 mi
Driving the converter
Type kilometers into the input and the mile figure updates live, no button. The dropdown swaps either unit, so going miles to kilometers or switching to another distance unit keeps you on this page. There’s a reference table beneath the field for the values people look up most, races and round numbers included.
Results round to a practical precision. The underlying mile is exactly 1.609344 km, so for high precision you can work from that exact figure directly.
FAQ
How many miles in a kilometer?
0.621371 miles. A bit under two thirds of a mile. A quick estimate: multiply kilometers by 0.6 and you’re close.
How far is a 10K in miles?
6.214 miles. A 5K is exactly half that, 3.107 miles. Worth memorizing if you sign up for road races.
What’s 100 km in miles?
62.14 miles. A useful anchor: 100 km is about 62 miles, so you can scale most highway distances from there in your head.
Is the conversion exact?
The mile is defined as exactly 1.609344 km, so 1 km equals 0.621371 mi as the exact inverse, rounded for display. No measurement error, just truncated decimals.
How many miles is a marathon?
26.219 miles, from the official 42.195 km distance. The “26.2” you see on stickers is that rounded down a touch.
Does it talk to a server?
No. It’s plain browser JavaScript. Load it once and it converts offline, with nothing sent anywhere.