Feet per Second to Kilometers per Hour
Convert feet per second (ft/s) to kilometers per hour (km/h). Both measure velocity, and the conversion comes up in driving, aviation, sports work.
The Formula
``
kilometers per hour = feet per second × 1.09728
feet per second = kilometers per hour × 0.911344415281
`
One feet per second is 1.0973 kilometers per hour, and one kilometers per hour is 0.911344 feet per second.
Conversion Table
| 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 |
The Other Direction
| 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 |
What Each Unit Is
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.
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.
A Sense of Scale
A pitched baseball leaves the hand near 130 ft/s- Walking is about 4.6 ft/s
- Urban limits are 30–50 km/h
- Motorways are 100–130 km/h
- A cyclist cruises at 20 km/h
Doing It in Your Head
Multiply by 11, then divide by 10. 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 10.9728 km/h 11 km/h 109.728 km/h 110 km/h
Precision
The factor 1.09728 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 footPerSecondToKilometerPerHour = (value) => value * 1.09728;
``
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 ft/s with the factor truncated at each decimal place:
| Decimals kept | Factor | 137 ft/s becomes | Error |
|---|---|---|---|
| 0 | 1 | 137 | 8.8656% |
| 1 | 1.1 | 150.7 | 0.2479% |
| 2 | 1.1 | 150.7 | 0.2479% |
| 3 | 1.097 | 150.289 | 0.0255% |
| 4 | 1.0973 | 150.33 | 0.0018% |
The right number of significant figures is set by your input, not by the converter. If you measured feet per second to three significant figures, the answer in kilometers per hour is only good to three — writing more digits claims precision the measurement never had.