Kilometers per Hour Conversion Tool - Convert km/h to Any Unit
Convert Kilometers per Hour to Other Units
Quick Conversions
Convert Other Units to Kilometers per Hour
Quick Conversions
Related Velocity / Speed Units
Kilometer per Hour Conversion Table
This comprehensive km/h conversion table shows how various units relate to kilometers per hour. Use this reference for quick conversions between km/h and other common speed units.
| Conversion | To Unit | Multiplier |
|---|---|---|
| km/h to m/s | m/s | 0.277778 |
| km/h to mph | mph | 0.621371 |
| km/h to ft/s | ft/s | 0.911344 |
| km/h to knots | knots | 0.539957 |
| km/h to mach | mach | 0.000816 |
| km/h to c | c | 9.2657e-10 |
This km/h conversion reference table provides accurate conversion factors for both metric (SI) units and imperial units. All values are based on internationally recognized standards for maximum precision in scientific and engineering applications.
What is Kilometer per Hour?
The kilometer per hour (symbol: km/h) is a unit of speed expressing the number of kilometers traveled in one hour. It is the most commonly used unit of speed on road signs and car speedometers worldwide. Although not an SI unit (the SI derived unit for speed is meters per second), km/h is accepted for use with SI units.
Kilometers per hour is used extensively for measuring vehicle speeds and is the standard unit for this purpose in most countries around the world. Our km/h conversion tool helps you easily convert between kilometers per hour and other units. For example, 100 km/h equals approximately 62.14 mph or 27.78 m/s.
What is the SI of Kilometer per Hour?
The kilometer per hour is not an SI base unit, but it is accepted for use with SI units. The SI derived unit for speed is meters per second (m/s). All other velocity units can be converted to and from km/h using appropriate conversion factors:
- Kilometer per hour (km/h) = 1 km/h
- Meter per second (m/s) = 3.6 km/h
- Mile per hour (mph) = 1.60934 km/h
- Foot per second (ft/s) = 1.09728 km/h
- Knot (kt) = 1.852 km/h
What is Kilometer per Hour Used For?
Kilometers per hour is used in a wide range of applications, primarily for measuring the speed of vehicles and other moving objects. As the standard unit for vehicle speeds in most countries, km/h is essential for transportation, traffic management, and everyday travel:
Transportation & Traffic
Road speed limits, vehicle speedometers, and traffic signs. For example, a highway speed limit of 120 km/h (approximately 75 mph) is common in many countries.
Weather Reporting
Wind speeds are often reported in km/h, especially in countries using the metric system. For example, a strong wind might be reported as 60 km/h.
Sports & Athletics
Measuring the speed of balls in sports like tennis or baseball, or the speed of athletes in sprinting events. For example, a tennis serve might be recorded at 200 km/h.
Maritime & Aviation
While knots are more common in these fields, km/h is sometimes used for public communication. For example, describing an aircraft's cruising speed to passengers.
Etymology and History
The term "kilometer per hour" came into use after the development of the metric system and the need to measure speed. The concept of speed itself has ancient origins, but standardized units for measuring it developed much later. The kilometer was officially defined in 1799, and the hour has been used as a time unit since ancient times.
The km/h unit became widely adopted in the 19th century with the development of railways and later automobiles. It was officially accepted for use with SI units, making it one of the most recognized non-SI units in the world. This evolution reflects the advancement of transportation technology and the need for standardized speed measurements.
Frequently Asked Questions
Why is km/h used instead of m/s for vehicle speeds?
Kilometers per hour is more practical for vehicle speeds because it produces reasonable numbers for typical driving speeds. If we used m/s, highway speeds would be around 28-33 m/s, which is less intuitive for most people. km/h provides numbers that are easier to understand and remember for everyday driving situations.
How do I convert km/h to other units?
Use our km/h conversion calculators above, or multiply by the appropriate conversion factor. For example, to convert km/h to m/s, divide by 3.6; to convert km/h to mph, multiply by 0.621371. For detailed instructions on converting km/h to mph, visit our km/h to mph converter.
What's the difference between km/h and kph?
There is no difference in meaning. "km/h" is the correct SI symbol, while "kph" is a common informal abbreviation. Both refer to the same unit of speed. The formal symbol follows SI conventions with a forward slash to indicate division between units.
How accurate are km/h conversions?
Our km/h converter provides highly accurate results using internationally recognized conversion factors. For example, 1 km/h equals exactly 0.277778 m/s (1/3.6). This precision is essential for applications ranging from scientific research to automotive engineering where exact measurements are critical.
Why do some countries use mph instead of km/h?
A few countries, primarily the United States and the United Kingdom, use miles per hour (mph) instead of km/h. This is due to historical reasons and their continued use of the imperial system for many measurements. The conversion between km/h and mph is straightforward, with 1 mph equal to exactly 1.609344 km/h.
How does km/h compare to other speed units?
Kilometers per hour is part of the metric system and relates to other metric units. 1 km/h equals 0.277778 m/s, 0.621371 mph, 0.911344 ft/s, 0.539957 knots, and 0.000816 mach (at sea level, 20°C). These relationships make conversions between units in the same system particularly straightforward.
Can I convert very high speeds in km/h?
Yes, our km/h converter handles both typical vehicle speeds and extremely high speeds. For example, you can convert the speed of sound (approximately 1,235 km/h at sea level) or even speeds approaching the speed of light (approximately 1.08 billion km/h). Our smart rounding feature ensures readable results for all scales.
Is your km/h conversion tool free to use?
Yes, our km/h conversion calculator is completely free with no registration required. Simply enter your value, select your target unit, and get instant, accurate results. We believe precise measurement conversion should be accessible to everyone, from students learning about speed to professionals working on engineering projects.