Ounce

An ounce (oz) is a unit of weight used in American recipes and older British ones. One ounce is 28.35 g, and 16 ounces make a pound. The same ounce is used in both the US and the UK. It is easy to confuse with the fluid ounce, which measures volume, not weight.

Why it works

An ounce of anything weighs the same, whether it is feathers or butter. A fluid ounce of anything takes up the same space, but the weight changes with the ingredient. Only for water and similar liquids do 1 oz and 1 fl oz match up closely. So "8 oz chocolate" means weigh it, and "8 fl oz milk" means measure it in a jug.

How to use it

For quick work, 1 oz is about 28 g, or 30 g if you are rounding loosely. For baking, use 28 g.

Ounces	Grams
½ oz	14 g
1 oz	28 g
2 oz	57 g
4 oz (¼ lb)	113 g
8 oz (½ lb)	227 g
12 oz (¾ lb)	340 g
16 oz (1 lb)	454 g

Most digital kitchen scales can switch between ounces and grams with one button. Weighing in grams is usually easier, because a scale in ounces shows fractions or decimals.

Common mistakes

• Measuring "8 oz flour" in a measuring cup marked 8 fl oz. A cup of flour weighs about 4½ oz, so you would use too little.
• Reading the ounce weight on a can as volume. "15 oz" on a can of beans is the net weight, including liquid. See can sizes.
• Confusing the troy ounce, used for precious metals, which is about 31 g. It is never used in cooking.

In recipes

You will see "8 oz cream cheese, softened", "4 oz dark chocolate, chopped" and "a 6 oz piece of salmon". American meat portions are often given in ounces: a 4 oz serving of meat is about 113 g, and a quarter-pound burger is 4 oz before cooking. Older British recipes write "4 oz plain flour" or "4oz".