KM/H to MPH converter

How to convert kilometers per hour to miles per hour

To convert kilometers per hour to miles per hour, use mph = km/h × 0.621371. For example, 100 km/h is 62.1371 mph. Type any value in the converter above and the result updates instantly.

The KM/H to MPH formula

The conversion is mph = km/h × 0.621371. One kilometer per hour equals 0.621371 mph. This conversion is exact: kilometer per hour is defined precisely in terms of mile per hour, so the only rounding is in the digits shown.

KM/H to MPH conversion table

Where kilometers per hour and miles per hour are used

Kilometers per hour is the speed unit on road signs and vehicle instruments in most of the world.

Miles per hour is the speed unit on road signs in the United States and the United Kingdom.

Worked examples

These examples use the formula above, so you can check the converter or do the same by hand:

• 20 km/h = 12.4274 mph
• 50 km/h = 31.0686 mph
• 80 km/h = 49.7097 mph

Converting kilometers per hour to miles per hour in your head

Multiply by 0.6: 100 km/h is about 60 mph (exactly 62.1 mph).

MPH to KM/H reference table

For the opposite direction, these values are handy to have at hand:

Common mistakes to avoid

• Speed limits, aviation and sailing use different units: knots are used at sea and in the air, not on roads.
• Rounded rules of thumb are fine for driving estimates but not for precise engineering calculations.

About this converter

The converter accepts whole numbers, decimals and negative values, gives the result as you type, and uses full precision internally, so what you copy is as accurate as it can be. It runs in your browser: nothing you type is sent to a server, it keeps working offline once the page has loaded, and there is nothing to install.

Need the opposite direction? Use the MPH to KM/H converter.