How many ounces are in a cup? Fluid vs weight
Quick answer: 1 US cup is 8 fluid ounces. That is a measure of volume. If a recipe gives ounces as a weight, the answer depends on the ingredient, because a cup of flour does not weigh the same as a cup of butter.
Two different ounces
The word “ounce” is used for two different things:
- Fluid ounce (fl oz): a unit of volume. A cup is 8 fl oz. This is what liquid measuring cups show.
- Ounce (oz): a unit of weight. It is 28.35 grams. A pound is 16 ounces.
A fluid ounce of water weighs about 1.04 ounces, so for water the two are close. For ingredients that are lighter or heavier than water, they are not.
Cups, fluid ounces and milliliters
| Cups | Fluid ounces | Tablespoons | Milliliters |
|---|---|---|---|
| 1/4 cup | 2 fl oz | 4 tbsp | 59 ml |
| 1/2 cup | 4 fl oz | 8 tbsp | 118 ml |
| 3/4 cup | 6 fl oz | 12 tbsp | 177 ml |
| 1 cup | 8 fl oz | 16 tbsp | 237 ml |
| 2 cups (1 pint) | 16 fl oz | 32 tbsp | 473 ml |
| 4 cups (1 quart) | 32 fl oz | 64 tbsp | 946 ml |
How much does a cup weigh in ounces?
These are typical figures for one US cup. They are approximations, because how you scoop and pack changes them.
| Ingredient | Approx. weight per cup |
|---|---|
| Water | 8.3 oz (237 g) |
| All-purpose flour | 4.25 oz (120 to 125 g) |
| Granulated sugar | 7 oz (200 g) |
| Butter | 8 oz (227 g) |
Butter is the one convenient exception. A cup of butter, which is two sticks, weighs exactly 8 ounces, so the fluid ounce and weight ounce happen to match.
Which one does my recipe mean?
- If the ingredient is a liquid and the recipe says “8 oz”, it almost always means fluid ounces.
- If the ingredient is dry (flour, sugar, chocolate, cheese) and the recipe says “8 oz”, it means weight, and you need a kitchen scale.
Convert a weight in ounces to grams with our ounces to grams converter. For cup and fluid ounce conversions, use the cups to fluid ounces converter.
Frequently asked questions
How many ounces are in half a cup? 4 fluid ounces.
Is 8 oz the same as 1 cup? For liquids, yes: 8 fluid ounces is 1 cup. For dry ingredients, only by coincidence.
How many cups are in 16 oz? 2 cups of liquid, which is 1 pint.
Why volume and weight differ is explained in cups to grams: why there is no single answer.