revolution/hour [r/h] Unit Converter

Definition of revolution/hour [r/h] unit

Revolution per hour (rev/h) is a unit of angular velocity describing how many complete turns an object makes around an axis during one hour. Unlike degrees or radians, it counts full rotations, making it useful for slow rotational motion.

History of revolution/hour [r/h] unit

The revolution is an ancient way of describing circular motion, while the hour comes from early sexagesimal timekeeping traditions developed in Mesopotamia. As mechanical clocks, astronomy, and engineering advanced, rotations were increasingly measured against standardized time intervals. Revolution per hour emerged as a practical, intuitive unit for slow-moving mechanisms, including clock hands, astronomical bodies, and machinery. Although the SI system favors radians per second, rev/h remains available in calculators, technical references, and specialized instruments where expressing complete turns is clearer than using fractional radians.

Applications of revolution/hour [r/h] unit

Revolution per hour is used to express slow rotational speeds in astronomy, horology, instrumentation, and mechanical engineering. For example, a clock’s hour hand turns at 1 rev per 12 hours, or 0.0833 rev/h, while an astronomical object may rotate only a few revolutions per hour. It also appears in rotary sensors, laboratory equipment, and conversion tools.

Complete list of revolution/hour [r/h] unit conversion