KM to MPH Converter

Relationship Between Kilometers per Hour and Miles per Hour

The conversion between kilometers per hour (km/h) and miles per hour (mph) is based on the relationship where 1 mile equals 1.609344 kilometers exactly.

1 mph = 1.609344 km/h

Therefore,

1 km/h = 1/1.609344 mph ≈ 0.621371 mph

To convert kilometers per hour to miles per hour, we multiply the value in km/h by 0.621371.

For example, 100 km/h equals approximately 62.14 mph.

Kilometer per Hour (km/h)

What is a Kilometer per Hour (km/h)?

Kilometer per hour (symbol: km/h) is a unit of speed in the International System of Units (SI), expressing the number of kilometers traveled in one hour. It is the standard unit for measuring vehicle speeds in most countries worldwide.

History and Origin

The kilometer per hour became widely adopted with the metric system and the rise of automobile transportation. It provides a convenient way to express vehicle speeds using the metric system's base unit of length (kilometer) and the standard unit of time (hour).

Current Use

• Traffic speed limits: Used in most countries for road signs and speed regulations
• Vehicle speedometers: Standard unit displayed on cars, motorcycles, and bicycles in metric countries
• Weather reports: Wind speeds and storm movement speeds
• Sports: Running, cycling, and other athletic performance metrics
• Aviation: Some aircraft speeds, especially at lower altitudes
• Marine navigation: Some boat and ship speeds

Mile per Hour (mph)

What is a Mile per Hour (mph)?

Mile per hour (symbol: mph) is a unit of speed in the imperial and US customary systems, expressing the number of miles traveled in one hour. It is the standard unit for measuring vehicle speeds in the United States, United Kingdom, and a few other countries.

Origin

The mile per hour has been used for centuries, particularly in English-speaking countries. It originated with the imperial system and became the standard speed measurement for transportation as automobiles became common in the early 20th century. Despite global metrication, mph remains the legal standard for road speeds in the US and UK.

Current Use

Miles per hour is primarily used in the United States and United Kingdom for road speed limits, vehicle speedometers, and traffic regulations. It's also used in some Commonwealth countries and in certain industries worldwide, particularly aviation (nautical miles per hour for airspeed). Common speed limits include 30 mph in residential areas, 55-70 mph on highways, and various limits for different road types.

Kilometer per Hour to Mile per Hour Conversion Table

The conversion of kilometers per hour to miles per hour for certain values are provided below: