How Many Ounces in a Cup?

There are 8 US fluid ounces in 1 US cup. So half a cup is 4 fl oz, a quarter cup is 2 fl oz, and three-quarters of a cup is 6 fl oz. That's for liquids, measured by volume — for dry ingredients, "ounces" on a recipe or package usually means weight, and a cup of flour, sugar or oats each weighs a different number of ounces (see the dry-ounce chart on this page).

8 fluid ounces of any liquid is exactly 1 cup. But 8 ounces by weight depends on the ingredient: 8 oz of all-purpose flour is about 1.9 cups, while 8 oz of butter is exactly 1 cup (2 sticks). If a recipe says "8 oz" of a dry ingredient, it almost always means weight — use a scale, or an ingredient-specific converter.

A fluid ounce measures volume (how much space something fills); an ounce measures weight. They only line up for water-like liquids: a fluid ounce of water weighs just about 1 ounce (1.043 oz to be exact). For anything else the two diverge — a cup of flour fills 8 fl oz of space but weighs only about 4.2 oz.

Half a US cup is 4 fluid ounces, which is also 8 tablespoons or about 118 mL. By weight, half a cup of butter is 4 oz (one stick), but half a cup of flour is only about 2.1 oz.

A quarter cup is 2 fluid ounces, or 4 tablespoons (about 59 mL).

A third of a cup is about 2.67 fluid ounces — 5 tablespoons plus 1 teaspoon, or about 79 mL.

Three-quarters of a cup is 6 fluid ounces, or 12 tablespoons (about 177 mL).

16 fluid ounces is 2 cups — that's 1 US pint. By weight, 16 oz is 1 pound, and how many cups that fills depends on the ingredient: a pound of flour is about 3.8 cups, a pound of granulated sugar about 2.3 cups, and a pound of butter exactly 2 cups (4 sticks).

Almost, but not exactly — a US cup of water weighs about 8.35 oz (236.6 g), because a fluid ounce of water weighs slightly more than a weight ounce. The neat "a pint's a pound" rhyme is off by about 4%. Butter is the ingredient where the numbers really do match: 1 cup = 8 oz = 2 sticks.

One 8 oz (227 g) block of cream cheese is just about 1 cup — cream cheese weighs roughly 232 g per cup, so a standard block is 0.98 cups. Recipes that call for a cup of cream cheese mean one block.

Close but not identical. An imperial (UK) fluid ounce is 28.41 mL versus 29.57 mL for the US fluid ounce — about 4% smaller. Old British recipes also use the 10-fl-oz imperial cup and the 20-fl-oz imperial pint, so a UK pint (568 mL) is bigger than a US pint (473 mL).

A "cup" on a coffee maker is usually only 5 or 6 fluid ounces, not the 8 fl oz measuring cup — and a typical coffee mug actually holds 8–12 fl oz. Coffee-maker cups are a marketing measure, so don't use them for recipes.