Miles per Hour to Kilometers per Hour Converter

About the mph to km/h calculation

One mile per hour is exactly 1.6093 kilometers per hour, so converting between them is a single multiplication. Enter any value above and the result updates as you type. Speed limits and vehicle speedometers in the US and UK. Exactly 1.609344 km/h. The speed-limit unit across most of the world.

Formula

km/h = mph × 1.6093

1 mph = 1.6093 km/h
1 km/h = 0.621371 mph

Worked example

To convert 60 mph, multiply by 1.6093: 60 × 1.6093 = 96.5606 km/h.

Frequently asked questions

How many kilometers per hour are in a mile per hour?

There are 1.6093 kilometers per hour in one mile per hour. To convert any amount, multiply the number of miles per hour by 1.6093.

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

Divide instead of multiplying, or equivalently multiply by 0.621371. One kilometer per hour is 0.621371 miles per hour.

Is this conversion exact?

Yes. Since the international agreement of 1959, the relationship between miles per hour and kilometers per hour is defined exactly rather than measured, so the only rounding here is in how many decimal places we show.

Where is each of these units used?

Miles per Hour: speed limits and vehicle speedometers in the US and UK. Exactly 1.609344 km/h. Kilometers per Hour: the speed-limit unit across most of the world.

Sources

• NIST Special Publication 811 — Guide for the Use of the International System of Units