How Many Gallons in a Pound?

Divide the pounds by what one gallon of the ingredient weighs. The divisor in the formula above is the weight of a US gallon of water. Milk and dry foods each need their own divisor, which the converter looks up for you.

A gallon of whole milk weighs about 8.607 lb. So 20 lb of milk fills 20 ÷ 8.607 = 2.32 gallons, a little less than the same weight of water would.

Weights this large usually come up with bulk liquids, big batches and storage. For the reverse question, how much a gallon weighs, use the gallons to pounds converter.

The imperial gallon used in the UK is the larger of the two, as the table below shows. It also has a handy property: an imperial gallon of water weighs almost exactly 10 pounds (10.02 lb).

That makes British water math easy. Each pound of water is about 0.1 imperial gallon, so 100 lb of water fills about 10 imperial gallons. The US gallon is smaller, so the same weight fills more US gallons.

A gallon is a big volume, so small differences in density grow into whole pounds. Milk is a little heavier than water, gallon for gallon, while dry foods are far lighter.

A gallon of all-purpose (plain) flour weighs only about 4.4 lb, and a gallon of granulated sugar about 7.1 lb. Turned around, a single pound of flour takes up about 0.227 gallon, far more room than a pound of water needs.

If you keep bulk flour or sugar in a bucket marked in gallons, convert the weight before you buy the bucket. By USDA cup weights, 25 lb of all-purpose flour takes up about 5.7 gallons. The same weight of granulated sugar needs only about 3.5 gallons.

Treat these as rough figures. Flour poured from a sack can settle tighter or looser than flour in a measuring cup, so leave some headroom at the top.