Convert Feet per Second to Kilometers per Hour
Feet per second to kilometers per hour is the conversion you need when a speed measured in the imperial system — often from physics problems, wind readings, or ball speeds — has to be expressed the way most of the world talks about speed. One foot per second is exactly 1.09728 kilometers per hour, so the number always gets a bit bigger when you switch from ft/s to km/h.
Feet per second to Kilometers per hour conversion table
| Feet per second (ft/s) | Kilometers per hour (km/h) |
|---|---|
| 1 | 1.09728 |
| 2 | 2.19456 |
| 3 | 3.29184 |
| 5 | 5.4864 |
| 10 | 10.9728 |
| 20 | 21.9456 |
| 50 | 54.864 |
| 100 | 109.728 |
| 500 | 548.64 |
| 1,000 | 1,097.28 |
The formula
To convert feet per second to kilometers per hour, multiply the speed in feet per second by 1.09728:
kilometers per hour = feet per second × 1.09728
A worked example
Say a wind gauge reads 100 feet per second and you want that in kilometers per hour:
100 × 1.09728 = 109.73 km/h
That's a genuinely fierce gust — well into hurricane-force territory once you check it against a wind scale.
Why the number is exact
Feet per second and kilometers per hour both reduce to a distance-over-time ratio, and the distance part is fixed precisely: one foot equals exactly 0.3048 metres by international agreement. Because that definition has no rounding built in, every feet-per-second to kilometers-per-hour conversion is exact — the factor 1.09728 is a fixed number, not an estimate.
When you'll use it
Converting physics problem answers, translating US wind or projectile speed readings into metric units for a lab report, and comparing ball or pitch speeds quoted in feet per second against speed limits or weather reports given in kilometers per hour.
Frequently asked questions
How many kilometers per hour are in a foot per second?
Exactly 1.09728 km/h. This is an exact value, not a rounded estimate, because both units trace back to the same precise definition of the foot in metres.
Is the feet-per-second to kilometers-per-hour conversion exact?
Yes. One foot is defined as exactly 0.3048 metres, and that definition carries through cleanly to give 1.09728 km/h per ft/s. Any rounding you see is only in how the result is displayed, not in the underlying math.
What's a quick way to estimate feet per second in kilometers per hour?
Roughly add 10%. 100 ft/s is close to 110 km/h. For anything precise — like a physics assignment or a wind speed reading — use the exact factor above.