Convert Kilometers per Hour to Miles per Hour

The Conversion Formula

To convert kilometers per hour to miles per hour, multiply the value by the conversion factor: 1 km/h = 0.621372 mph. For a worked example, suppose you need to convert 25 km/h to miles per hour: 25 × 0.621372 = 15.5343 mph. To convert in the opposite direction, divide by 0.621372, or equivalently multiply by 1.6093.

About kilometers per hour

Kilometers per hour (km/h) is the standard unit for speed limits and car speedometers in almost every country except the US and UK. It gained dominance as the metric system spread in the 20th century. Even in the UK, which uses mph on signs, car speedometers must also show km/h. kilometers per hour are commonly used in Speed limits (Global), Car speedometers, High-speed trains, and Bicycle computers, Weather reports (some countries).

Highway speed limits are often 100-130 km/h.

About miles per hour

Miles per hour (mph) is the standard speed unit for the United States and United Kingdom. It has been used since the days of stagecoaches but became codified with the rise of the automobile and the need for speed limits. Despite metrication efforts, the UK retains mph for its roads, keeping it aligned with the US system. miles per hour are commonly used in US & UK Speed limits, Baseball pitch speeds, Tennis serve speeds, and Hurricane wind speeds (US), NASCAR.

US highway speeds are typically 65-75 mph.

When Would You Convert kilometers per hour to miles per hour?

Converting between kilometers per hour and miles per hour is one of the most common speed conversions. You might need this conversion when working with international specifications, following instructions written for a different measurement system, or comparing values across different standards. Having the conversion factor (1 km/h = 0.621372 mph) memorized or bookmarked can save time in professional and everyday contexts alike.