Feet per Second to Miles per Hour
Convert feet per second (ft/s) to miles per hour (mph). Both measure velocity, and the conversion comes up in driving, aviation, sports work.
The Formula
``
miles per hour = feet per second × 0.681818181818
feet per second = miles per hour × 1.46666666667
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One feet per second is 0.681818 miles per hour, and one miles per hour is 1.4667 feet per second.
Conversion Table
| Feet per Second | Miles per Hour |
|---|---|
| 1 ft/s | 0.681818 mph |
| 2 ft/s | 1.3636 mph |
| 5 ft/s | 3.4091 mph |
| 10 ft/s | 6.8182 mph |
| 25 ft/s | 17.0455 mph |
| 50 ft/s | 34.0909 mph |
| 100 ft/s | 68.1818 mph |
| 500 ft/s | 340.9091 mph |
| 1,000 ft/s | 681.8182 mph |
The Other Direction
| Miles per Hour | Feet per Second |
|---|---|
| 1 mph | 1.4667 ft/s |
| 2 mph | 2.9333 ft/s |
| 5 mph | 7.3333 ft/s |
| 10 mph | 14.6667 ft/s |
| 25 mph | 36.6667 ft/s |
| 50 mph | 73.3333 ft/s |
| 100 mph | 146.6667 ft/s |
| 500 mph | 733.3333 ft/s |
| 1,000 mph | 1,466.67 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.
Miles per Hour (mph) — miles travelled per hour, equal to 1.609344 km/h exactly. The road-speed unit of 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
- Residential limits are 25–30 mph
- US freeways are 65–75 mph
- A jog is 6 mph
Precision
The factor 0.681818181818 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 footPerSecondToMilePerHour = (value) => value * 0.681818181818;
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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 | 46.6667% |
| 1 | 0.7 | 95.9 | 2.6667% |
| 2 | 0.68 | 93.16 | 0.2667% |
| 3 | 0.682 | 93.434 | 0.0267% |
| 4 | 0.6818 | 93.4066 | 0.0027% |
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 miles per hour is only good to three — writing more digits claims precision the measurement never had.