Dictionary:API gravity

A measure of the density of liquid hydrocarbons at standard pressure and temperature derived from the equation:

$ \mathrm {API} \ \mathrm {gravity} ={\frac {141.5}{\mathrm {SG} }}-131.5 $

where

$ \mathrm {SG} ={\frac {\rho _{\mathrm {oil} }}{\rho _{\mathrm {H_{2}O} }}} $

API gravity is measured in degrees API. 5° to 22° is considered heavy oil; 22° to 31°, medium; greater than 31°, light condensate.