What is mile per hour?
Mile per hour is a unit of speed equal to one mile travelled in one hour. It is the standard unit for road speeds, vehicle performance ratings, and weather reports in the United States and United Kingdom.
Real-world uses
Miles per hour is the standard speed unit for road traffic in the United States, the United Kingdom, and a few other countries. Baseball pitching speed, hurricane wind categories (Saffir-Simpson scale), and NASCAR race speeds are quoted in mph.
History
Miles per hour became the standard speed expression in English-speaking countries with the advent of railways and later automobiles. The first US speed limit (8 mph in New York City, 1901) and British speed cameras use mph as the legal standard.
Common mistakes
Assuming mph-to-km/h conversion is a simple ×1.5—the actual factor is 1.609. Also, forgetting that UK and US speed limits both use mph, which can mislead visitors from metric countries into driving too fast or too slow.
What is foot per second?
Foot per second is a unit of speed in imperial and US customary systems. It is used in ballistics, sports science, and engineering calculations that rely on US customary units.
Real-world uses
Feet per second is used in ballistics for bullet muzzle velocities (e.g., 2,800 fps for a rifle round), aerospace engineering for aircraft approach speeds, and fluid dynamics in American engineering contexts. Elevator speeds are sometimes specified in ft/s.
History
Feet per second has been used in English-language engineering since the 18th century, particularly in artillery and ballistics. It remains the standard velocity unit in American firearms and aerospace industries despite the broader shift toward metric units.
Common mistakes
Confusing feet per second with miles per hour. 1 ft/s ≈ 0.682 mph, so they are quite different. Also, using fps as an abbreviation for both "feet per second" and "frames per second" creates ambiguity in technical documents.
When is this conversion used?
Speed limits, vehicle speedometers, and weather reports for wind speeds use different units depending on the country, making km/h to mph conversion one of the most practical speed conversions.
Worked examples
1 mile per hour = 1.46666667 foot per second
1 foot per second = 0.3048 metre per second
How to convert mile per hour to foot per second
To convert mile per hour to foot per second, multiply the value by 1.46666667.
To convert foot per second back to mile per hour, multiply by 0.68181818.
Measurement standards
The SI unit of speed is metres per second (m/s), a derived unit requiring no independent definition. The knot is defined as exactly one nautical mile (1,852 metres) per hour and is sanctioned for maritime and aeronautical navigation by the International Civil Aviation Organization.
Did you know?
The fastest human-made object is the Parker Solar Probe, which reached 635,266 km/h (about 176 km/s) in 2024 during a close pass of the Sun — fast enough to travel from New York to Tokyo in under a minute.
Quick reference: mile per hour to foot per second
| mile per hour | foot per second |
|---|---|
| 0.1 | 0.14666667 |
| 0.5 | 0.73333333 |
| 1 | 1.46666667 |
| 2 | 2.93333333 |
| 5 | 7.33333333 |
| 10 | 14.66666667 |
| 25 | 36.66666667 |
| 50 | 73.33333333 |
| 100 | 146.66666667 |
| 250 | 366.66666667 |
| 500 | 733.33333333 |
| 1,000 | 1,466.66666667 |
Common values
| mile per hour | foot per second | |
|---|---|---|
| Walking speed | 3.13171081 mile per hour | 4.59317585 foot per second |
| City speed limit | 31.09341446 mile per hour | 45.60367454 foot per second |
| Highway driving | 70.01610594 mile per hour | 102.69028871 foot per second |
| Commercial aircraft | 559.23407301 mile per hour | 820.20997375 foot per second |
| Speed of sound (sea level) | 761.20705082 mile per hour | 1,116.43700787 foot per second |
Available Speed units
More mile per hour conversions
- Convert mile per hour to metre per second
- Convert mile per hour to kilometre per hour
- Convert mile per hour to knot
- Convert mile per hour to foot per second
- Convert mile per hour to metre per minute
- Convert mile per hour to kilometre per second
- Convert mile per hour to mach (approx at sea level)
- Convert mile per hour to centimetre per second
- Convert mile per hour to mile per minute
Assumption: Mach uses an approximate sea-level reference (about 340.29 m/s).