Miles to KM converter
For UK drivers on European roads, runners between race distances and anyone whose sat-nav disagrees with the signs. Exact factor, both directions.
Guide
How to use it
- Type miles on the left or kilometres on the right, both directions update live.
- For speed limits rather than distances, switch the units to miles per hour and km/h on the main converter's speed category, or just treat the numbers the same, the factor is identical.
- Head maths on the road: miles × 8 ÷ 5 is km, close enough for driving.
Examples
Worked examples
The sat-nav says 757 km. 757 × 0.621371 = 470 miles, so think Leeds to Penzance before deciding to do it in one hop.
A 10K is 6.21 miles; a half marathon (21.0975 km) is 13.11 miles. Your 8-minute-mile pace is 4:58 per km.
130 km/h on the autoroute is 130 ÷ 1.609344 = 80.8 mph. The rain limit of 110 km/h is 68 mph.
Method
How it works
The international mile is defined as exactly 1,609.344 metres, so miles to kilometres is one multiplication by 1.609344 and the reverse is a division. The popular 5-to-8 head trick works because 8 ÷ 5 = 1.6, within 0.6% of the true factor.
Runs entirely in your browser, works offline in the car park with no signal.
FAQ
Frequently asked questions
How many km is a mile?
Exactly 1.609344 km. Going back, a kilometre is about 0.621371 miles, so a quick head estimate is km × 0.6.
What is a quick way to convert in my head?
Miles to km: multiply by 8 and divide by 5. Km to miles: the reverse, times 5 over 8. 60 miles → 96 km is within half a per cent of the exact 96.56.
How fast is a 100 km/h limit in mph?
About 62 mph. Common European limits: 50 km/h is 31 mph, 90 is 56, 110 is 68 and 130 km/h is 81 mph. The speed category on the main converter handles any of them.
How far is a marathon in each?
26.219 miles or 42.195 km. A half is 13.1 miles, 21.1 km, and a 10K is 6.21 miles.
Why do UK roads still use miles?
UK road signs and speed limits stayed imperial when most other measures went metric, so drivers cross to France and instantly need this conversion in both directions.
Is the conversion exact?
Yes. The international mile is defined as exactly 1,609.344 metres, so nothing here is approximated except your chosen rounding.
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