Fluid Ounces to Pounds (fl oz to lb)

The divisor in the formula is the number of fluid ounces of water that make one pound. Use it for water only. Every other food has its own divisor, because a fluid ounce of it weighs more or less than water.

Whole milk is a good example. About 14.9 fluid ounces of it make a pound, so half a US gallon, 64 fl oz, weighs 64 ÷ 14.9 = 4.3 pounds. The same jug filled with water would weigh 4.17 pounds.

If you know an ingredient's weight in grams per cup, you can also convert to grams first and then to pounds. The answer is the same either way.

An imperial fluid ounce is a little smaller than a US fluid ounce, so it takes more of them to weigh a pound. About 16 imperial fluid ounces of water make one pound.

That makes the British pint of 20 imp fl oz a handy benchmark. A full imperial pint of water weighs about 1.25 pounds, a pound and a quarter.

A fluid ounce is a fixed amount of space, and a pound is a fixed amount of weight. How many fluid ounces it takes to reach a pound depends on how heavy the food is for its size. Milk needs slightly fewer fluid ounces than water, because it is a little heavier.

Dry, fluffy foods need far more. It takes about 29 fluid ounces of all-purpose flour to make a pound, which is more than 3 1/2 cups. Granulated sugar sits in between, at about 18.1 fluid ounces per pound.

For a picnic cooler or a box of bottles to ship, add up the fluid ounces first and convert once. Twelve bottles of 20 fl oz hold 240 fl oz in total, which is about 15.6 pounds if the drink is mostly water.

Then add the containers and the ice. Glass bottles and cans add weight that no conversion covers, so weigh one empty container if you need a close total.