How Many Pounds in a Gallon?

For water, multiply the gallons by the factor above. For any other food, swap in the weight of one gallon of that food instead. The table below lists six common ones, and the converter lets you pick an ingredient.

A weekly dairy run of 4 gallons of whole milk shows how it works. One gallon of whole milk weighs about 8.61 pounds, so the total is 4 × 8.61 = 34.4 pounds.

The same rule works for bulk dry goods stored by the gallon, as long as you use that food's own weight per gallon.

An imperial gallon holds 160 imp fl oz, while a US gallon holds 128 fl oz, and the imperial fluid ounce is only slightly smaller. The result is a bigger gallon: filled with water, it weighs about 10 pounds, an easy number to remember.

Everything else scales up the same way. An imperial gallon of whole milk would weigh about 10.3 pounds.

Pounds per gallon is a handy way to compare foods, because the gallon stays fixed and only the contents change. Water sets the baseline. Milk lands slightly above it, and butter just below it at about 8.01 pounds per gallon.

Dry foods drop well under water. A gallon of powdered sugar weighs about 4.23 pounds, since a fine powder traps a lot of air. Whole raw blueberries come to about 5.22 pounds per gallon, because round berries leave gaps between them.

Slightly. According to the USGS Water Science School, water is densest at about 39 °F (4 °C) and becomes less dense as it warms. A gallon of hot tap water therefore weighs a little less than a gallon of ice-cold water.

This site counts water at 1 kilogram per liter, the USDA figure. Figures elsewhere can differ in the last digit, depending on rounding and on the water temperature assumed, but the gap is far too small to matter in a kitchen.