How to Convert Kilometres per hour to Feet per second (km/h to ft/s)
Speed conversions come up with expressway limits in km/h, foreign car specs in mph and wind speeds reported in knots by the Meteorological Service. This guide shows how to convert kilometres per hour into feet per second by hand, with examples and a quick-reference table.
The conversion
To convert kilometres per hour to feet per second, multiply the value by 0.9113444153. To go the other way, divide by the same number (or multiply by 1.09728). For a quick estimate, multiply by about 0.91.
Feet per second = kilometres per hour × 0.9113444153
Worked examples
- 3 km/h = 2.734 ft/s
- 12.5 km/h = 11.3918 ft/s
- 75 km/h = 68.3508 ft/s
Kilometres per hour to Feet per second table
| Kilometres per hour | Feet per second |
|---|---|
| 1 km/h | 0.911344 ft/s |
| 2 km/h | 1.8227 ft/s |
| 5 km/h | 4.5567 ft/s |
| 10 km/h | 9.1134 ft/s |
| 20 km/h | 18.2269 ft/s |
| 25 km/h | 22.7836 ft/s |
| 50 km/h | 45.5672 ft/s |
| 100 km/h | 91.1344 ft/s |
| 250 km/h | 227.8361 ft/s |
| 500 km/h | 455.6722 ft/s |
| 1,000 km/h | 911.3444 ft/s |
Common questions
Is km/h to ft/s exact?
The factors used here are the internationally defined values where they exist; results are rounded for display only.
How do I convert back?
Use the Feet per second to Kilometres per hour converter.
Mistakes to avoid
Forgetting squared and cubed units
Area and volume factors are the length factor squared or cubed, so 1 m² is about 10.76 sq ft, not 3.28.
Dropping the units
A bare number without a unit is easy to misread later. Always write the unit with the result.
Rounding the factor too early
Using 3 instead of 3.28 for feet per metre introduces an error of almost 9% before you have started.
Background
Writing the units next to every number while you work is the simplest way to avoid mistakes. If the units do not cancel to leave the one you want, the calculation is set up wrongly.
A conversion table is handy for common values, but a calculator is faster and avoids interpolation errors for anything in between.
Unit conversion is simply multiplication by a fixed ratio. The ratio between two units of the same quantity never changes, so once you know it you can convert any value in either direction.
For any value, use the Kilometres per hour to Feet per second Converter or browse all speed converters.
Run your own numbers: Kilometres per hour to Feet per second Converter