Ans

Unit converter

Kilometres per hour to miles per hour.

Convert km/h to mph and mph to km/h. Type in either box and the other follows. A speedometer reading of 100 km/h is 62.1 mph, comfortably inside a UK 70 limit.

km/h → mphExact definition
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Kilometres per hour to miles per hour — common values, to 6 significant figures.
km/hmph
10 km/h6.21371 mph
20 km/h12.4274 mph
30 km/h18.6411 mph
50 km/h31.0686 mph
60 km/h37.2823 mph
70 km/h43.496 mph
80 km/h49.7097 mph
90 km/h55.9234 mph
100 km/h62.1371 mph
110 km/h68.3508 mph
120 km/h74.5645 mph
130 km/h80.7783 mph
1 km/h=0.6213711922 mph 1 mph=1.609344 km/h

Definitions

  • The kilometre per hour is the speed unit on road signs across most of the world. Dividing by 3.6 gives metres per second.
  • The mile per hour is the speed limit unit in the UK and the US. Exactly 0.447 04 m/s.
  • This conversion is exact by definition. 1 km/h = 0.6213711922 mph.
  • Speed is converted through m/s.

How it works

One direction multiplies and the other divides by the same number, so nothing is lost by going back and forth.

The value passes through m/s, the unit every other speed unit on the site is defined against, rather than a number written into this page on its own. That is why the figure here, the figure in the table above and the general speed converter always agree.

Display precision sets a maximum number of significant figures and trims trailing zeroes, so it changes what you see and never what was calculated. The editable box always holds a plain number at full working precision, so you can carry on from either side.

Common questions this answers: how many miles per hour in a kilometre per hour (0.621371), how many kilometres per hour in a mile per hour (1.60934), and what 100 km/h is in miles per hour (62.1371 mph).

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