Ans

Unit converter

Miles per hour to kilometres per hour.

Convert mph to km/h and km/h to mph. Type in either box and the other follows. UK speed limits are in miles per hour and continental ones are in kilometres per hour — 70 mph is 112.7 km/h.

mph → km/hExact definition
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Miles per hour to kilometres per hour — common values, to 6 significant figures.
mphkm/h
10 mph16.0934 km/h
20 mph32.1869 km/h
30 mph48.2803 km/h
40 mph64.3738 km/h
50 mph80.4672 km/h
60 mph96.5606 km/h
70 mph112.654 km/h
80 mph128.748 km/h
90 mph144.841 km/h
100 mph160.934 km/h
1 mph=1.609344 km/h 1 km/h=0.6213711922 mph

Definitions

  • The mile per hour is the speed limit unit in the UK and the US. Exactly 0.447 04 m/s.
  • The kilometre per hour is the speed unit on road signs across most of the world. Dividing by 3.6 gives metres per second.
  • This conversion is exact by definition. 1 mph = 1.609344 km/h.
  • 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 kilometres per hour in a mile per hour (1.60934), how many miles per hour in a kilometre per hour (0.621371), and what 70 mph is in kilometres per hour (112.654 km/h).

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