gallon (US)/minute Unit Converter

Definition of gallon (US)/minute unit

Gallon (US)/minute, commonly written gal/min or gpm, is a volumetric flow-rate unit describing how many United States liquid gallons of fluid pass a point in one minute. One US gallon equals 3.785411784 liters.

History of gallon (US)/minute unit

The US gallon originated as a historical volume measure in English-speaking regions, but the United States established its own liquid gallon definition in the nineteenth century. In 1893, the Mendenhall Order linked US customary measurements to metric standards, and the modern gallon was ultimately fixed at exactly 231 cubic inches, or 3.785411784 liters. Engineers and industrial users combined this volume unit with the minute to express practical fluid throughput. The abbreviation gpm became common in water supply, plumbing, irrigation, and process engineering. Today, it remains a common flow specification.

Applications of gallon (US)/minute unit

This unit is widely used for specifying pump capacity, water delivery, and liquid circulation in residential, agricultural, municipal, and industrial systems. A pump rated at 20 gpm delivers a nominal 20 US gallons each minute. Plumbers use gpm for fixtures and pipes, while irrigation designers use it to size zones.

Complete list of gallon (US)/minute unit conversion