Miles to Kilometers

What this tool is used for

• Converting a US route distance for a metric map or navigation setting.
• Reading an imperial odometer figure into the units an expense form requires.
• Converting a race distance to compare against a metric event.
• Checking a mileage allowance against a distance quoted in kilometres.
• Converting a radius given in miles for a metric service-area definition.

Frequently Asked Questions

What is the formula?

Multiply by 1.609344. For estimation, add 60%: 50 miles → 50 + 30 = 80 km (true 80.5). The error stays under 1% and is easy to do in your head at speed limits.

Which mile is being converted?

The international statute mile, 1609.344 m. The US survey mile differed by about 3 mm per mile and was retired in 2022; the nautical mile (1852 m) and the Roman mile (~1480 m) are entirely separate units.

How do common speed limits convert?

30 mph is 48 km/h, 60 mph is 97 km/h, 70 mph is 113 km/h. Note that converted limits are almost never posted as the exact figure — countries round to a signable number, so 70 mph becomes 110 km/h rather than 113.

How do I convert fuel economy?

Not by scaling, because the units invert: mpg is distance per volume while L/100km is volume per distance. The relationship is L/100km = 235.215 / mpg (US gallons). Doubling mpg halves L/100km — the two do not move linearly together.

Why is the mile 1760 yards?

The Roman mille passuum (a thousand paces) was about 1480 m; the English mile was later fixed at 8 furlongs, and a furlong at 220 yards, giving 1760. The furlong survives in horse racing, which is why the number looks arbitrary.

How do I convert a running time per mile to per kilometre?

Divide the pace by 1.609, not multiply — a slower-sounding number per kilometre covers less ground. An 8:00 mile is roughly a 4:58 kilometre, which surprises people expecting the number to rise.

Why do marathon distances not round?

Because 26.2 miles is an approximation of 42.195 km, which is the defined distance. The imperial figure is the derived one, so converting it back gives 42.165 km — a 30-metre discrepancy that matters to record keeping.

Common errors and gotchas

• Using 1.6 rather than 1.609344, which loses most of a kilometre over a hundred miles.
• Confusing statute with nautical miles, which appear together in aviation and marine contexts.
• Converting a fuel-economy figure with the distance factor alone, when the volume unit also changes.
• Summing converted legs rather than converting the sum, which accumulates rounding.
• Treating an odometer reading as exact when the instrument has its own tolerance.