Convert miles per hour to kilometers per hour

Precise decimal and fraction answers

The conversion in kilometers per hour rounded to six significant decimal places is 1 mph = 1.609344 km/h. The precise fraction answer is 1 ⁶¹³/₁₀₀₆ km/h.

How many kilometers per hour is a mile per hour?

1.609 kilometers per hour is the same velocity as one mile per hour. A mile per hour is 1.609 times faster than a kilometer per hour. An object traveling at one kilometer per hour kilometer per hour has 62.14% of the velocity of an object moving at one mile per hour.

Miles per hour to kilometers per hour conversion factor and formulas

The conversion factor between miles per hour and kilometers per hour is 1.609. This represents the ratio of kilometers per hour per one mile per hour. To calculate the value in kilometers per hour, we can either multiply by the conversion factor or divide by its inverse.

Multiplication

To convert from miles per hour to kilometers per hour, multiply miles per hour by 1.609.
The formula is expressed as:
mph × 1.609 = km/h

Division

Alternatively we can divide by the inverse conversion factor to get the same result.
The inverse of 1.609 is 1/1.609 or 0.621. To convert from miles per hour to kilometers per hour, divide miles per hour by 0.621.
The formula is expressed as:
mph ÷ 0.621 = km/h

About this conversion

Converting miles per hour to kilometers per hour is a conversion between units from separate unit systems - miles per hour are US Customary / UK Imperial defined units while kilometers per hour are metric (SI) .

About Miles per hour

Miles per hour is a velocity measurement within the US/UK Imperial systems. It is defined as the number of miles traveled in one hour. MPH is frequently used for measurement and regulation of vehicle speed limits in the US, UK and many British dependencies. The common symbols for miles per hour are mph, MPH or mi/hr.

About Kilometers per hour

Within the SI (metric) system of measurement, a kilometer per hour (km/h) is the distance traveled in one hour as measured in kilometers (1,000 meters). It is commonly used as measurement of velocity over geographic distances. Kilometers per hour are commonly used to measure vehicle speed and speed limits. The official SI symbol is km/h, however kph and km/hr are also used.

Reverse this conversion

Convert from kilometers per hour to miles per hour instead.

References and Citations

1. National Institute of Standards and Technology (NIST) General Tables of Units of Measurement
2. International Bureau of Weights and Measures (BIPM) The International System of Units (SI)