Convert units of measurement from one system to another
A unit conversion changes the numerical representation of a physical quantity without changing the quantity itself. For example, a length can be expressed in millimeters, centimeters, meters, inches or feet; mass can be expressed in kilograms or pounds; and fixed time durations can be expressed in seconds, minutes, hours or days.
Choose the dimension first. Units from different physical quantities are not interchangeable: kilograms cannot be converted to miles, and a generic “unit” cannot be converted to milliliters or milligrams unless the context defines what that unit represents.