Feet per second.
ft/s to mph Converter — ft/s to mph
Convert ft/s (ft/s) to mph (mph) using the exact conversion factor (1 ft/s = 0.6818181818 mph). See the formula, worked examples, conversion table, history, and common uses.
ft/s to mph converter
Converter
Speed Converter
Convert road, aviation, marine, lab, and scientific speed units.
Context values
Some unit families need one extra value for a physically accurate result.
Miles per hour.
Result = input x 0.3048 / 0.44704.
Speed uses meters per second as the base unit.
Reserved above the conversion cards and below the converter.
About Converting ft/s to mph
ft/s and mph both describe speed, and the conversion matters whenever a maritime or aviation speed (knots) needs to be compared against a road speed (mph). Specifically: Feet per second, and miles per hour.
Formula
mph = ft/s × 0.681818181818
This factor comes from each unit's defined relationship to the category's base unit: 1 ft/s equals 0.3048 base units, and 1 mph equals 0.44704 base units, so dividing one by the other gives the direct ft/s-to-mph factor of 0.681818181818.
Simple example
1 ft/s × 0.6818181818 = 0.6818181818 mph
1 ft/s = 0.6818181818 mph.
Real-world example
10 ft/s × 0.6818181818 = 6.818181818 mph
10 ft/s = 6.818181818 mph.
Conversion table
| ft/s (ft/s) | mph (mph) |
|---|---|
| 1 ft/s | 0.6818181818 mph |
| 5 ft/s | 3.409090909 mph |
| 10 ft/s | 6.818181818 mph |
| 25 ft/s | 17.04545455 mph |
| 50 ft/s | 34.09090909 mph |
| 100 ft/s | 68.18181818 mph |
Reverse conversion: mph to ft/s
0.6818181818 mph × 1.466666667 = 1 ft/s
0.6818181818 mph = 1 ft/s.
ft/s = mph × 1.46666666667
For a page dedicated to this direction, see mph to ft/s.
Understanding the ft/s (ft/s)
Feet per second.
Understanding the mph
mph (mph) measures speed. Miles per hour follows directly from the international statute mile (1,609.344 m) divided by one hour. It is classified as a US/imperial customary unit.
Where it's used: United States (road speed limits and vehicle speedometers) United Kingdom (road speed limits)
Uses of the mph today
- Road speed limits and vehicle speedometers in the US and UK
- Weather reporting (wind speed) in the US
- Sports statistics (e.g. pitch speed, wind gusts) in US media
History of the mph
Miles per hour is a compound unit with no separate origin story of its own — it follows automatically once the statute mile was fixed at 5,280 feet in 1593 and later refined to exactly 1,609.344 meters by the 1959 international agreement that also standardized the pound.
Historical origin. mph was not the invention of a single named person; it developed through the process described above.
mph — sources
- NIST — International yard and pound (1959) — Basis for the modern mile used in mph.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many mph are in 1 ft/s?
1 ft/s equals 0.6818181818 mph, using the exact defined conversion factor rather than an estimate.
How do I convert ft/s to mph?
Multiply the ft/s value by 0.6818181818. The converter above does this instantly to whatever precision you set.
How do I convert mph back to ft/s?
Use the reverse factor: 1 mph equals 1.466666667 ft/s. You can also use the swap control in the converter above to flip the direction instantly.
What is a ft/s?
ft/s (ft/s) is a unit of speed.
What is a mph?
mph (mph) measures speed. Miles per hour follows directly from the international statute mile (1,609.344 m) divided by one hour. It is classified as a US/imperial customary unit.
Is the ft/s to mph conversion exact?
Yes. Both ft/s and mph are defined by fixed standards rather than physical artifacts, so the factor of 0.6818181818 used above is exact to as many digits as you choose to display.