Convert Foot/Second (ft/s) to Kilometer/Second (km/s) instantly.
About these units
Foot/Second (ft/s)
The foot per second is an imperial speed unit used in engineering, ballistics, aviation, and certain sports sciences. It expresses the number of feet traveled per second. Ballistics experts use ft/s to measure bullet velocities and projectile speeds, particularly in countries with strong imperial-unit traditions. Engineers may use ft/s in fluid flow calculations or mechanical system design when working with legacy data. Although ft/s is rarely seen in daily life, it remains relevant in niche disciplines where imperial units dominate, offering a smaller, more precise scale than mph.
Kilometer/Second (km/s)
A kilometer per second represents a very high speed—1,000 meters every second—and is particularly important in astronomy, planetary science, and astrophysics. Orbital velocities around planets, escape velocities, solar winds, and the motion of stars relative to each other are commonly measured in km/s. This scale captures speeds far beyond terrestrial transportation. For example, Earth orbits the Sun at roughly 30 km/s, and meteoroids entering Earth's atmosphere may arrive at speeds between 11 and 72 km/s. km/s is a natural step up from m/s when describing the motion of celestial bodies.