Convert Miles per Hour to Miles per Second
Convert Miles per Hour (mph) to Miles per Second (mi/s) instantly and accurately.
Conversion Formula
mi/s = mph × 0.0002777777778
About Miles per Hour
A mile per hour (mph) = exactly 0.44704 m/s - the primary road speed unit in the US, UK, and a few other countries. US interstate limits 65-85 mph; UK motorway 70 mph. Walking ~3-4 mph; club cycling 20-25 mph. MLB elite fastball 100 mph (44.7 m/s). Saffir-Simpson Category 5 hurricane ≥157 mph. Boeing 737 MAX cruises at ~521 mph (Mach 0.79). 1 mph = 0.44704 m/s = 1.60934 km/h = 0.86898 kn.
About Miles per Second
A mile per second (mi/s) = exactly 1,609.344 m/s - above the fastest air-breathing aircraft. NASA X-43A scramjet: 2.9 km/s ≈ 1.8 mi/s (Mach 9.6). Earth's orbital speed around the Sun: ~18.5 mi/s (29.8 km/s). Light travels ~186,282 mi/s in vacuum - the classic imperial figure still used in popular astronomy. Tunguska impactor entered Earth's atmosphere at ~9-11 mi/s. 1 mi/s = 3,600 mph = 3,128.3 kn.
Quick Reference Table
| Miles per Hour (mph) | Miles per Second (mi/s) |
|---|---|
| 1 mph | 0.000277778 mi/s |
| 2 mph | 0.000555556 mi/s |
| 5 mph | 0.00138889 mi/s |
| 10 mph | 0.00277778 mi/s |
| 25 mph | 0.00694444 mi/s |
| 50 mph | 0.0138889 mi/s |
| 100 mph | 0.0277778 mi/s |