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MPH to KM/H Converter

Convert miles per hour to kilometers per hour instantly, with a reference table of common speed limits.

MPH to KM/H Converter

1 mph = 1.609 km/h

Multiply miles per hour by 1.609344 to get kilometers per hour.

Miles per hour to kilometers per hour reference table

The conversions people look up most often, rounded to 3 decimal places.

Common miles per hour to kilometers per hour conversions
Mile per hour (mph)Kilometer per hour (km/h)
5 mph8.047 km/h
10 mph16.093 km/h
20 mph32.187 km/h
25 mph40.234 km/h
30 mph48.28 km/h
35 mph56.327 km/h
40 mph64.374 km/h
50 mph80.467 km/h
55 mph88.514 km/h
60 mph96.561 km/h
65 mph104.607 km/h
70 mph112.654 km/h
80 mph128.748 km/h

How the mph to km/h converter calculation works

Speed converts on the same factor as distance, because the "per hour" is identical on both sides:

km/h = mph × 1.609344

A worked example for anyone driving abroad: a 70 mph motorway limit is 70 × 1.609344 = 112.7 km/h, which is why UK and US highway speeds map so closely onto the 110-120 km/h limits used across continental Europe. A 30 mph urban limit is 48.3 km/h, essentially the 50 km/h standard used almost everywhere in the metric world.

The conversions that matter most when renting a car:

  • 25 mph ≈ 40 km/h — residential streets
  • 55 mph ≈ 89 km/h — US secondary highways
  • 65 mph ≈ 105 km/h — US interstates
  • 80 mph ≈ 129 km/h — the upper end of European motorway limits

Two practical tips:

  • Multiply by 1.6 in your head. 60 mph → 96 km/h against a true 96.6. That is accurate enough to keep you legal.
  • Read the speedometer, not the conversion. Nearly every car sold in the last two decades prints both scales on the dial, and rental cars in metric countries show km/h as the primary. Convert to sanity-check a road sign, not to drive by.

To convert km/h back to mph, divide by 1.609344 — or multiply by 0.621371.

Frequently asked questions

How do I convert miles per hour to kilometers per hour?

Multiply the number of miles per hour by 1.609344 to get kilometers per hour.

How many kilometers per hour are in 30 mph?

30 mph equals 48.280 km/h. The reference table on this page lists the other values people look up most often.

How do I convert kilometers per hour back to miles per hour?

Divide the number of kilometers per hour by 1.609344, or use the swap control on the converter above.

Is this conversion exact?

Yes. The factor is fixed by international definition rather than measured, so the conversion is exact - only the displayed rounding limits precision.

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