gal [Gal] Unit Converter

Definition of gal [Gal] unit

The gal (Gal) is a unit of acceleration in the centimetre–gram–second system, equal to one centimetre per second squared (1 cm/s²). It is used primarily to express gravitational acceleration and small variations in Earth’s gravity.

History of gal [Gal] unit

The gal is named after Galileo Galilei (1564–1642), whose work established foundational principles of motion and falling bodies. It was introduced as a practical unit in geodesy and gravimetry, fields concerned with measuring Earth’s shape and gravitational field. The centimetre–gram–second (CGS) system defined it as one centimetre per second squared. In 1971, the International Astronomical Union recommended the symbol Gal, distinguishing it from the gallon. Modern SI practice generally uses m/s², but the gal remains familiar in specialized gravity measurements and geophysics.

Applications of gal [Gal] unit

Today, gals are used in gravimetry, geodesy, seismology, and geophysics to report local gravitational acceleration and subtle changes caused by mountains, underground structures, tides, groundwater, or earthquakes. Gravity maps commonly use Gal or mGal (milligal), while precision instruments may record values in µGal. For reference, standard Earth gravity is approximately 980 Gal, or 9.80665 m/s².

Complete list of gal [Gal] unit conversion