Converter

Convert kilometres per hour to miles per hour

kilometres per hour (km/h)

miles per hour (mph)

0.621371

Formula: mph = km/h × 0.621371

km/h to mph quick reference table

kilometres per hour (km/h)	miles per hour (mph)
1	0.621371
2	1.2427
5	3.1069
10	6.2137
20	12.4274
25	15.5343
50	31.0686
100	62.1371
250	155.343
500	310.686
1,000	621.371

Everyday km/h values, converted

50 km/h = 31.0686 mph — a city speed limit.
100 km/h = 62.1371 mph — a motorway speed limit.

Where km/h to mph comes up

Speed conversions matter when driving abroad, reading a foreign weather report or setting a treadmill. Getting a speed limit wrong is the one conversion with a fine attached.

Doing km/h to mph in your head

Multiply by 6 and drop a digit, or use the 5:8 rule — 5 miles is about 8 kilometres. 100 km becomes roughly 62 miles.

Precision and rounding

One kilometre per hour is exactly 0.621371 miles per hour under the current definitions of both units, so the only judgement call is how many digits you keep. Two decimal places is already finer than most household scales and tape measures can read, while engineering and medical work usually keeps the full factor and rounds once at the end rather than at every step.

Frequently Asked Questions & How-To

1 kilometre per hour equals 0.621371 miles per hour. 10 kilometres per hour is 6.2137 miles per hour, and 100 kilometres per hour is 62.1371 miles per hour.

The conversion uses mph = km/h × 0.621371. Type any amount above and the result updates as you type — no button press and no page reload.

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