Fluid Ounces to Ounces (fl oz to oz)

First make sure you really have two different ounces. A fluid ounce is read off a measuring cup or a bottle, and an ounce is read off a scale. The factor above converts one into the other for water.

For a 16 fl oz bottle of water, the weight is about 16.7 ounces. Other foods need their own factor, the weight in ounces of one fluid ounce of that food. Whole milk comes to about 1.08 ounces per fluid ounce, granulated sugar to 0.88 and all-purpose flour to only 0.55.

Multiply the fluid ounces by that factor to get ounces of weight. To go back, divide instead, or use the ounces to fluid ounces page.

The British imperial fluid ounce sits even closer to the weight ounce. Filled with water it weighs 1.002 ounces, so in a UK recipe a fluid ounce of water and an ounce of water are practically the same amount.

The US fluid ounce is a little larger than the imperial one. That is why a US fluid ounce of water weighs slightly more than an ounce, and why the gap grows as the amounts get bigger.

The two units share a name but do different jobs. A fluid ounce tells you how much room something takes up, and an ounce tells you how heavy it is. Water lines up with the weight ounce almost one to one, so the names seem interchangeable.

Most dry foods break that match. A fluid ounce of powdered sugar weighs about 0.53 ounce, only about half of what the name suggests. Shredded cheese is similar: a cup of it, which is eight fluid ounces, weighs about 4 ounces.

US labels follow a rule about which ounce to print. The FDA Food Labeling Guide says the net quantity of a liquid food is generally given in fluid measure, such as fl oz, and that of a solid, semisolid or viscous food in weight.

So a bottle of juice shows fluid ounces, while a jar of peanut butter or a bag of chips shows ounces of weight. Only the second number can be checked on a kitchen scale.