How to convert km to miles
A mile is exactly 1.609344 kilometres. To turn kilometres into miles, divide by 1.609344 (or multiply by 0.621371). To turn miles into kilometres, multiply by 1.609344.
miles = km ÷ 1.609344
km = miles × 1.609344
Quick trick: multiply kilometres by 5 and divide by 8. 80 km × 5 ÷ 8 = 50 miles, which is very close to the exact answer of 49.7. Going the other way, multiply miles by 8 and divide by 5.
Worked examples
10 km in miles
10 ÷ 1.609344 = 6.21 miles. That's the distance of a 10k race.
26.2 miles in km
26.2 × 1.609344 = 42.16 km. The official marathon distance is 42.195 km, or 26 miles 385 yards.
130 km/h in mph
130 ÷ 1.609344 = 80.8 mph. That's the motorway limit in France and many other European countries.
Running race distances
| Race | Kilometres | Miles |
|---|---|---|
| Parkrun / 5k | 5 km | 3.11 miles |
| 10k | 10 km | 6.21 miles |
| Half marathon | 21.1 km | 13.1 miles |
| Marathon | 42.2 km | 26.2 miles |
| 50k ultra | 50 km | 31.07 miles |
To turn a finish time into pace per km or per mile, use the running pace calculator.
Speed limits when driving abroad
The UK uses mph, but Ireland and the rest of Europe use km/h. Hire cars abroad usually show km/h large on the speedometer, so it helps to know the conversions.
| km/h | mph | Where you'll see it |
|---|---|---|
| 30 km/h | 19 mph | Town centres in France and Spain |
| 50 km/h | 31 mph | Built-up areas across most of Europe |
| 80 km/h | 50 mph | Rural roads in France |
| 100 km/h | 62 mph | National roads in Ireland and many main roads in Europe |
| 120 km/h | 75 mph | Motorways in Ireland, Spain and Portugal |
| 130 km/h | 81 mph | Motorways in France and Italy |
UK limits for comparison: 30 mph is 48 km/h, 60 mph is 97 km/h and 70 mph is 113 km/h. Always follow the signs, as limits change with weather and local rules.
Fuel and running costs
Planning a road trip? The fuel cost calculator works out the cost of a journey, and the MPG calculator converts between miles per gallon and litres per 100 km.
Frequently asked questions
How many miles is a kilometre?
One kilometre is 0.621 miles. Divide kilometres by 1.609 to get miles.
How many km is a mile?
One mile is 1.609 kilometres (1.609344 exactly).
How many miles is a 5k?
5 km is 3.11 miles, and a 10k is 6.21 miles.
What is 100 km/h in mph?
100 km/h is 62.1 mph.
What's an easy way to convert km to miles in my head?
Multiply the kilometres by 5 and divide by 8. For example, 40 km × 5 ÷ 8 = 25 miles (the exact answer is 24.85).
Last reviewed October 2026. This calculator gives an estimate for guidance only.