Kilometers per Hour to Feet per Second
Convert kilometers per hour (km/h) to feet per second (ft/s). Both measure velocity, and the conversion comes up in driving, aviation, sports work.
The Formula
``
feet per second = kilometers per hour × 0.911344415281
kilometers per hour = feet per second × 1.09728
`
One kilometers per hour is 0.911344 feet per second, and one feet per second is 1.0973 kilometers per hour.
Conversion Table
| Kilometers 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 |
| 25 km/h | 22.7836 ft/s |
| 50 km/h | 45.5672 ft/s |
| 100 km/h | 91.1344 ft/s |
| 500 km/h | 455.6722 ft/s |
| 1,000 km/h | 911.3444 ft/s |
The Other Direction
| Feet per Second | Kilometers per Hour |
|---|---|
| 1 ft/s | 1.0973 km/h |
| 2 ft/s | 2.1946 km/h |
| 5 ft/s | 5.4864 km/h |
| 10 ft/s | 10.9728 km/h |
| 25 ft/s | 27.432 km/h |
| 50 ft/s | 54.864 km/h |
| 100 ft/s | 109.728 km/h |
| 500 ft/s | 548.64 km/h |
| 1,000 ft/s | 1,097.28 km/h |
What Each Unit Is
Kilometers per Hour (km/h) — kilometres travelled per hour, equal to 1/3.6 m/s. The road-speed unit in almost every country outside the US and UK.
Feet per Second (ft/s) — feet travelled per second, equal to 0.3048 m/s exactly. Used in US ballistics, fluid dynamics and some aviation contexts.
A Sense of Scale
Urban limits are 30–50 km/h- Motorways are 100–130 km/h
- A cyclist cruises at 20 km/h
- A pitched baseball leaves the hand near 130 ft/s
- Walking is about 4.6 ft/s
Doing It in Your Head
Multiply by 10, then divide by 11. That is off by 0.25% — close enough to judge a
distance, a weight or a price, and not close enough to sign off on a drawing.
Exact Mental shortcut 9.1134 ft/s 9.0909 ft/s 91.1344 ft/s 90.9091 ft/s
Precision
The factor 0.911344415281 is rounded. For engineering work carry more digits than the table above, and round only at the end — rounding at each step compounds.
In Code
`javascript
const kilometerPerHourToFootPerSecond = (value) => value * 0.911344415281;
``
Where This Conversion Comes Up
- Driving
- Aviation
- Sports
- Shipping
- Weather
How Many Decimals Do You Need?
Rounding the factor costs accuracy, and how much depends on the factor. Converting 137 km/h with the factor truncated at each decimal place:
| Decimals kept | Factor | 137 km/h becomes | Error |
|---|---|---|---|
| 0 | 1 | 137 | 9.7280% |
| 1 | 0.9 | 123.3 | 1.2448% |
| 2 | 0.91 | 124.67 | 0.1475% |
| 3 | 0.911 | 124.807 | 0.0378% |
| 4 | 0.9113 | 124.848 | 0.0049% |
The right number of significant figures is set by your input, not by the converter. If you measured kilometers per hour to three significant figures, the answer in feet per second is only good to three — writing more digits claims precision the measurement never had.