Miles Per Hour to Miles Per Second (mph to mi/s)

1 mile per hour equals 0.0002777777778 miles per second (rounded).

1 mile per hour = 0.0002777777778 miles per second

How to convert miles per hour to miles per second

To convert miles per hour to miles per second, multiply the number of miles per hour by 0.0002777777778. The factor is rounded to 10 significant digits. To go the other way, multiply miles per second by 3,600.

miles per second = miles per hour × 0.0002777777778

Example: 10 miles per hour = 0.002777777778 miles per second.

About these units

Mile Per Hour (mph)

US & ImperialCurrent unit

Exactly 0.44704 m/s. The unit for road speeds in the US, UK and a few other countries.

Early British motoring law is the best window into this unit. The 1861 Locomotive Act set a limit of 10 mph for light locomotives. The 1865 Red Flag Act cut it to 4 mph in the country and 2 mph in towns, with a person walking ahead with a flag. The Locomotives on Highways Act of 1896 raised it to 14 mph, and the Motor Car Act of 1903 to 20 mph. In 1931 all limits for cars were abolished, and 30 mph in built-up areas returned in 1935.

The mile per hour combines the mile, set at 5,280 feet in Elizabeth I's reign, with the hour, and it equals exactly 0.44704 m/s or 1.609344 km/h. The United Kingdom and United States use it on roads, along with several smaller countries, mostly territories or former territories of those two, and the US, Canada and Ireland use it for rail. Sports such as cricket, tennis and baseball quote ball speeds in it. Aviation and shipping prefer knots, about 0.869 of one mph each.

1 mile per hour = 0.44704 meters per second (exactly).

Sources: Wikipedia: Miles per hour; Wikipedia: Speed limits in the United Kingdom; Wikipedia: Mile

Mile Per Second (mi/s)

US & ImperialCurrent unit

Exactly 1,609.344 m/s. Used for very high speeds.

Spaceflight speeds are where mile per second appears. Escape velocity from Earth's surface is 11.186 km/s, which is about 6.95 mi/s, found by dividing 11,186 m/s by 1,609.344 m. From the Moon the figure is 2.38 km/s, or about 1.48 mi/s, and a low Earth orbit at 7.7 km/s is about 4.8 mi/s, about 69 percent of the Earth escape figure.

The international mile is exactly 1,609.344 m, so one mile per second is exactly that many meters per second, and NIST lists the conversion as exact. It is also 5,793.6 km/h, and one meter per second is therefore about 0.00062 mi/s. NIST cautions that mile per second is not among the units it generally uses in its own publications.

1 mile per second = 1,609.344 meters per second (exactly).

Sources: Wikipedia: Escape velocity; NIST SP 811 Appendix B.8: conversion factors; Wikipedia: Orders of magnitude (speed)

Related conversions

See all speed units.