The flow coefficient (Kv) is similar to Cv, but it is used for metric units and is defined as the number of liters per minute (L/min) of water at 20°C that will flow through a valve with a one-inch opening at a pressure drop of one bar. Cv and Kv are related by the following equation: Kv = 0.865 × Cv. This allows for easy conversion between the two coefficients, making it possible to compare valves from different manufacturers that may use different units.