Dry gallon measure of approximately the same size, though the dry gallon is a bit bigger. 1 dry gallon ≈ 1.163 647 fluid gallons Its implicit value in the US system was originally one eighth of the Winchester bushel, which was a cylindrical measure of 18.5 inches in diameter and 8 inches in depth. That made the dry gallon a non-terminating number of cubic inches, an irrational number whose value with the first six digits after the decimal point was 268.802521 ( cubic inches ≈ ). The bushel was later defined to be exactly 2150.42 cubic inches, making the dry gallon exactly
Gallon as . The IEEE standard symbol for the gallon is gal. The gallon currently has one definition in the imperial system, and two definitions (liquid and dry) in the US customary system. Historically, there were many definitions and redefinitions. There were more than a few systems of liquid measurements in the pre-1884 United Kingdom. The imperial (UK) gallon, now defined as exactly litres (about 277.42 cubic inches), is used in some Commonwealth countries and was originally based on the volume of 10 pounds (approximately 4.54 kg) of water at . The imperial fluid ounce is defined as of an imperial