How Many Kilograms in a Gallon?

If you think in metric units, the easiest route runs through liters. One US gallon is 3.785 L, and each liter of a food weighs a set number of kilograms: 1 for water and about 1.03 for whole milk.

For 3 gal of whole milk, that means 11.36 L × 1.03 = 11.7 kilograms. For dry goods the kilograms per liter are much lower, so check the table below before you multiply.

The formula above folds both steps into one factor for water. Use it for water, and use the two-step route for everything else.

The British imperial gallon is 4.546 L, about a fifth bigger than the US gallon. Filled with water, it weighs 4.546 kilograms.

When a recipe or a container only says "gallon," check where it comes from. A UK source means the imperial gallon, and using the US figure for it would leave you short by about three-quarters of a liter per gallon.

A gallon container always holds the same volume, but its contents decide the weight. Whole milk is a little heavier than water, as the milk question below shows. Butter is a little lighter than water, at about 3.63 kilograms per gallon.

Powders are far lighter because air fills much of the container. A gallon of powdered sugar (icing sugar) weighs only about 1.92 kilograms, roughly half the weight of the same gallon of water.

Say a large recipe for brine, iced tea or stock gives the water in gallons, and your kitchen scale reads in kilograms. Convert the water once and weigh it straight into the pot.

For 1.5 gal of water, that comes to about 5.68 kilograms. Weighing is often quicker than filling a measuring jug several times, and there is less to wash.