MPH to Feet per Second Converter
Convert miles per hour to feet per second and back instantly.
Common Speed Reference Table
| Miles per hour (mph) | Feet per second (ft/s) | Description |
|---|---|---|
| 1 | 1.47 | One mile per hour |
| 5 | 7.33 | Brisk walking pace |
| 15 | 22 | Cycling speed |
| 30 | 44 | Residential street limit |
| 60 | 88 | Highway cruising speed |
| 70 | 102.67 | Motorway speed limit |
| 100 | 146.67 | High-speed driving |
MPH and Feet per Second Conversion Formulas
Converting between miles per hour and feet per second uses a single constant factor. There are 5280 feet in a mile and 3600 seconds in an hour, so each mile per hour equals 5280 ÷ 3600 = 1.46666667 feet per second. Both conversions are a simple multiplication or division.
MPH to Feet per Second
ft/s = mph × 1.46666667
Example: 60 mph × 1.46666667 = 88 ft/s
Feet per Second to MPH
mph = ft/s ÷ 1.46666667
Example: 30 ft/s ÷ 1.46666667 = 20.4545 mph
Where the 1.46666667 Factor Comes From
The conversion factor is not arbitrary — it follows directly from the definitions of a mile and an hour. A mile is 5280 feet and an hour is 3600 seconds, so travelling one mile in one hour means covering 5280 feet in 3600 seconds:
5280 ft ÷ 3600 s = 1.46666667 ft/s
A useful mental shortcut is that 60 mph is exactly 88 ft/s, which makes it easy to estimate stopping distances and reaction times at common driving speeds.
Key Reference Speeds
- Walking pace: 3 mph = 4.4 ft/s. A comfortable everyday walking speed for most adults.
- Residential limit: 30 mph = 44 ft/s. A common speed limit on neighbourhood streets.
- Highway speed: 60 mph = 88 ft/s. The classic anchor value used in physics and driving examples.
- Motorway speed: 70 mph = 102.67 ft/s. A typical maximum limit on major roads.