What is kilometre per hour?
Kilometre per hour is a unit of speed equal to one kilometre travelled in one hour. It is the most widely used unit for road speed limits, vehicle speedometers, and wind speeds in metric countries.
Real-world uses
Kilometres per hour is the standard speed unit for road traffic in most countries, displayed on car speedometers, speed limit signs, and GPS devices. Weather services report wind speeds in km/h, and athletes track running pace in min/km.
History
Kilometres per hour became widespread as the metric system was adopted for road transport in the 20th century. The first metric speed limits appeared in continental Europe. Today, km/h is used in about 91% of the world's countries for traffic regulation.
Common mistakes
Confusing km/h with m/s—100 km/h is about 27.78 m/s, not 100 m/s. Also, when converting to mph, people often use a rough factor of 1.5 instead of the correct 1.609, leading to inaccurate speed comparisons.
What is foot per second?
Foot per second is a unit of speed in imperial and US customary systems. It is used in ballistics, sports science, and engineering calculations that rely on US customary units.
Real-world uses
Feet per second is used in ballistics for bullet muzzle velocities (e.g., 2,800 fps for a rifle round), aerospace engineering for aircraft approach speeds, and fluid dynamics in American engineering contexts. Elevator speeds are sometimes specified in ft/s.
History
Feet per second has been used in English-language engineering since the 18th century, particularly in artillery and ballistics. It remains the standard velocity unit in American firearms and aerospace industries despite the broader shift toward metric units.
Common mistakes
Confusing feet per second with miles per hour. 1 ft/s ≈ 0.682 mph, so they are quite different. Also, using fps as an abbreviation for both "feet per second" and "frames per second" creates ambiguity in technical documents.
When is this conversion used?
Converting between kilometre per hour and foot per second is common when working across metric and imperial systems, such as international trade, travel between countries with different measurement standards, or following instructions from a different region. Speed limits, vehicle speedometers, and weather reports for wind speeds use different units depending on the country, making km/h to mph conversion one of the most practical speed conversions.
Worked examples
1 kilometre per hour = 0.91134442 foot per second
1 foot per second = 0.3048 metre per second
How to convert kilometre per hour to foot per second
To convert kilometre per hour to foot per second, multiply the value by 0.91134442.
To convert foot per second back to kilometre per hour, multiply by 1.09728.
Measurement standards
The SI unit of speed is metres per second (m/s), a derived unit requiring no independent definition. The knot is defined as exactly one nautical mile (1,852 metres) per hour and is sanctioned for maritime and aeronautical navigation by the International Civil Aviation Organization.
Did you know?
The fastest human-made object is the Parker Solar Probe, which reached 635,266 km/h (about 176 km/s) in 2024 during a close pass of the Sun — fast enough to travel from New York to Tokyo in under a minute.
Quick reference: kilometre per hour to foot per second
| kilometre per hour | foot per second |
|---|---|
| 0.1 | 0.09113444 |
| 0.5 | 0.45567221 |
| 1 | 0.91134442 |
| 2 | 1.82268883 |
| 5 | 4.55672208 |
| 10 | 9.11344415 |
| 25 | 22.78361038 |
| 50 | 45.56722077 |
| 100 | 91.13444154 |
| 250 | 227.83610384 |
| 500 | 455.67220768 |
| 1,000 | 911.34441535 |
Common values
| kilometre per hour | foot per second | |
|---|---|---|
| Walking speed | 5.04 kilometre per hour | 4.59317585 foot per second |
| City speed limit | 50.04 kilometre per hour | 45.60367454 foot per second |
| Highway driving | 112.67999999 kilometre per hour | 102.69028871 foot per second |
| Commercial aircraft | 899.99999993 kilometre per hour | 820.20997375 foot per second |
| Speed of sound (sea level) | 1,225.0439999 kilometre per hour | 1,116.43700787 foot per second |
Available Speed units
More kilometre per hour conversions
- Convert kilometre per hour to metre per second
- Convert kilometre per hour to mile per hour
- Convert kilometre per hour to knot
- Convert kilometre per hour to foot per second
- Convert kilometre per hour to metre per minute
- Convert kilometre per hour to kilometre per second
- Convert kilometre per hour to mach (approx at sea level)
- Convert kilometre per hour to centimetre per second
- Convert kilometre per hour to mile per minute
Assumption: Mach uses an approximate sea-level reference (about 340.29 m/s).