Convert Kilometers to Miles
Instantly convert kilometers (km) to miles (mi), with the formula and real running and driving distances to anchor it.
- Millimeter (mm)1,000,000
- Centimeter (cm)100,000
- Meter (m)1,000
- Kilometer (km)1
- Inch (in)39,370.08
- Foot (ft)3,280.84
- Yard (yd)1,093.613
- Mile (mi)0.621371
- Ja/Chuk (자)3,300.33
- Chi/Chon (치)33,003.3
🔒 Unit conversions are computed in your browser.
The km-to-miles formula
To convert kilometers to miles, multiply by 0.6214: miles = kilometers × 0.6214. One kilometer is about 0.6214 mile — a little under two-thirds. So a 5 km run is 5 × 0.6214 = 3.11 miles, and 10 km is 6.21 miles. A speedometer reading of 100 km/h works out to roughly 62 mph. To go the other way, multiply miles by 1.609, since 1 mile equals 1.609 km. Keeping the rough 'two-thirds' rule in mind makes quick estimates easy on the fly.
Where you'll actually use it
The two big reasons are running and driving abroad. Converting race distances, a half marathon (21.0975 km) is about 13.11 miles and a full marathon (42.195 km) is 26.22 miles. If you rent a car in the US or UK, the road signs and dashboard read in miles, so translating your km instincts helps: a 60 mph limit is about 97 km/h, and 70 mph is roughly 113 km/h. It's also handy for reading fitness apps or race results posted in the other unit.
Rounding and which 'mile'
Two cautions. First, 0.6214 is rounded; the fuller factor is 0.621371. Over 5 km the gap is trivial, but across hundreds of kilometers the error adds up noticeably. Second, this is the statute mile used on roads. The nautical mile of aviation and shipping is different — 1 nautical mile equals 1.852 km, or about 1.15 statute miles — so don't mix them up. Unlike temperature, distance is a simple proportion through zero, so you only ever scale by the factor.
Frequently asked questions
How many miles is 1 km?
One kilometer is about 0.6214 mile — a bit under two-thirds, which is handy for quick mental math. In reverse, 1 mile is 1.609 km.
How many miles is a full marathon (42.195 km)?
42.195 × 0.6214 ≈ 26.22 miles. For reference, a half marathon (21.0975 km) is about 13.11 miles, 10 km is 6.21 miles, and 5 km is 3.11 miles.
Why do converters give slightly different answers?
It comes down to how many digits the conversion factor uses. Using 0.6214 versus 0.621371 shifts the decimals, and the longer the distance, the bigger the difference. For short runs it's negligible.