Meters Per Second to Kilometers Per Second (m/s to km/s)

1 meter per second equals 0.001 kilometers per second exactly.

1 meter per second = 0.001 kilometers per second

How to convert meters per second to kilometers per second

To convert meters per second to kilometers per second, multiply the number of meters per second by 0.001. This factor is exact. To go the other way, multiply kilometers per second by 1,000.

kilometers per second = meters per second × 0.001

Example: 10 meters per second = 0.01 kilometers per second.

About these units

Meter Per Second (m/s)

Metric (SI)Current unit

The SI unit of speed. Walking pace is about 1.4 m/s; a sprinter reaches roughly 10 m/s.

Official standing arrived in 1960, when the CGPM established the SI and made the meter per second the unit for speed and velocity. Before that, feet per second, miles per hour and knots were more common, depending on region and trade. One proposal gave 1 m/s its own name, the benz, after Karl Benz, but it was rejected and never caught on, so the unit is still written as a plain ratio of meter to second.

The meter is now defined by the distance light travels in a vacuum in 1/299,792,458 of a second, and the second by the vibration of caesium atoms, so the meter per second rests on two physical standards. Exactly 3.6 km/h make 1 m/s, and it equals about 2.2369 mph or 1.9438 knots. For scale, sound travels at about 343 m/s in dry air at 20 °C, and Chuck Yeager's Bell X-1 reached about 361 m/s, Mach 1.06, in October 1947. Physics and engineering use the unit almost exclusively.

The meter per second is the reference unit for speed on this site.

Sources: Wikipedia: Metre per second; NIST: the meter and the SI redefinition; Wikipedia: Sound barrier

Kilometer Per Second (km/s)

ScientificCurrent unit

1,000 m/s. Used for orbital velocities; low Earth orbit is about 7.7 km/s.

Orbital mechanics is where kilometers per second become the everyday scale. A satellite in a circular low Earth orbit between 200 and 2,000 km altitude travels at 7.7 to 6.9 km/s, and the International Space Station and typical low orbit satellites move at about 7.7 km/s, which is 27,700 km/h. Earth itself circles the Sun at an average of about 29.8 km/s, roughly 3.9 times that low orbit speed, since 29.8 divided by 7.7 is 3.87.

The unit also suits escape velocities, such as 11.186 km/s from the surface of Earth and 2.38 km/s from the Moon, and the speed of sound in water, about 1.5 km/s. It is a thousand times the SI base speed of 1 m/s, so quoting orbital motion in meters per second would mean long strings of digits.

1 kilometer per second = 1,000 meters per second (exactly).

Sources: Wikipedia: Orbital speed; Wikipedia: Escape velocity; Wikipedia: Orders of magnitude (speed)

Related conversions

See all speed units.