Miles to km converter
Convert miles to kilometres or kilometres to miles — for journey planning abroad, satnav and running distances, or reading a speed limit in the other unit.
Result
Distance
Result
Distance
How to use this tool
- Choose miles → km or km → miles.
- Enter the distance.
- Read the converted distance. The same factor converts speeds: mph ↔ km/h.
Assumptions
- Statute miles. Nautical miles (1.852 km) used at sea and in aviation are a different unit.
Sources & reference data
Technical details: what the fields mean
- Distance
miles - Distance in statute miles, the mile used on UK and US road signs.
Methodology
km = miles × 1.609344 (exact, by international definition of the yard); miles = km ÷ 1.609344.
Worked example
100 miles
Inputs: Distance: 100 miles
Result: 160.93 km
A marathon, 26.2 miles
Inputs: Distance: 26.2 miles
Result: 42.16 km — the official marathon is 42.195 km; 26.2 is the rounded mile figure.
Speed: the UK 70 mph motorway limit
Inputs: Distance: 70 miles
Result: 112.65 — so 70 mph ≈ 113 km/h.
km → miles: a 5 km run
Inputs: Distance: 5 km
Result: 3.11 miles.
km → miles: 100 km/h on a French road
Inputs: Distance: 100 km
Result: 62.14 — so 100 km/h ≈ 62 mph.
Practical guidance
- Quick mental check: multiply miles by 8 and divide by 5 for km (or km × 5 ÷ 8 for miles); it's within about 1%.
- Hire cars abroad usually show km/h on the speedometer — convert the limit you're used to before you set off.
Common mistakes
- Using the conversion for nautical miles, which are about 15% longer than statute miles.
- Rounding 1.609 down to 1.6 over long distances: 500 miles becomes 800 km instead of 804.67 km.
FAQs
How many km is 100 miles?
160.93 km.
How many miles is 5km?
3.11 miles.
Does this work for mph and km/h?
Yes — speed uses the same factor, so 70 mph is 112.65 km/h and 100 km/h is 62.14 mph.
Last reviewed: 2026-10-11
An exact unit conversion for statute miles — not for nautical miles.
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