How Many Ounces in a Cup?
There are 8 fluid ounces in one US cup. This guide covers fluid vs. weight ounces, different cup sizes, and a complete reference chart for cooking and baking.
Last updated: 2025-03-13
The Short Answer
There are 8 US fluid ounces in 1 US customary cup. This is the standard measurement used in American cooking and baking recipes. However, understanding the nuances behind this number — including the difference between fluid ounces and weight ounces, and the variations between cup sizes in different countries — will help you measure ingredients accurately every time.
Fluid Ounces vs. Weight Ounces
This is one of the most common sources of confusion in the kitchen. A fluid ounce (fl oz) measures volume — how much space a liquid takes up. A weight ounce (oz) measures mass — how heavy something is. They are not interchangeable:
- 1 US fluid ounce = 29.5735 milliliters (a measure of volume)
- 1 avoirdupois ounce = 28.3495 grams (a measure of weight)
For water, the two are close: 1 fluid ounce of water weighs approximately 1.043 weight ounces. But for other ingredients, the difference can be significant. One cup (8 fl oz) of flour weighs about 4.25 ounces (120 grams), while one cup (8 fl oz) of honey weighs about 12 ounces (340 grams).
Cup Fractions in Fluid Ounces
| Cup Measurement | Fluid Ounces | Tablespoons | Milliliters |
|---|---|---|---|
| 1/8 cup | 1 fl oz | 2 tbsp | 29.6 ml |
| 1/4 cup | 2 fl oz | 4 tbsp | 59.1 ml |
| 1/3 cup | 2.67 fl oz | 5.33 tbsp | 78.9 ml |
| 1/2 cup | 4 fl oz | 8 tbsp | 118.3 ml |
| 2/3 cup | 5.33 fl oz | 10.67 tbsp | 157.7 ml |
| 3/4 cup | 6 fl oz | 12 tbsp | 177.4 ml |
| 1 cup | 8 fl oz | 16 tbsp | 236.6 ml |
| 2 cups (1 pint) | 16 fl oz | 32 tbsp | 473.2 ml |
Common Ingredients: Weight Ounces per Cup
Since different ingredients have different densities, the weight of one cup varies. Here are some common ingredients:
| Ingredient | Weight per Cup |
|---|---|
| Water | 8.35 oz (237 g) |
| All-purpose flour | 4.25 oz (120 g) |
| Granulated sugar | 7.05 oz (200 g) |
| Brown sugar (packed) | 7.76 oz (220 g) |
| Butter | 8.0 oz (227 g) |
| Honey | 12.0 oz (340 g) |
| Milk | 8.6 oz (244 g) |
| Rolled oats | 3.0 oz (85 g) |
For accurate baking, a kitchen scale measuring in grams gives the best results. Use our cooking converter for quick conversions between units.
Cup Sizes Around the World
Not all cups are the same size, which matters when using recipes from different countries:
- US customary cup: 8 US fl oz = 236.588 ml
- US legal cup: 8.12 US fl oz = 240 ml (used on nutrition labels)
- Imperial cup: 10 imperial fl oz = 284.131 ml
- Metric cup: 8.45 US fl oz = 250 ml (Australia, New Zealand)
- Japanese cup: 6.76 US fl oz = 200 ml
An imperial cup contains 10 imperial fluid ounces (not 8), which is a common source of confusion when comparing British and American recipes.
Real-World Applications
Recipe Scaling
When doubling or halving a recipe, converting between cups and ounces helps maintain accuracy. If a recipe calls for 3/4 cup of milk and you are tripling it, that is 2.25 cups or 18 fluid ounces. Using ounces often makes the math easier with fractions.
Nutrition Tracking
Nutrition labels list serving sizes in both grams and fluid ounces. Knowing that 1 cup = 8 fl oz helps you estimate portions when eating or cooking without a scale.
Bartending and Beverages
Cocktail recipes typically use ounces. A standard jigger is 1.5 fl oz, a pony is 1 fl oz, and a dash is about 1/32 fl oz. Knowing that 8 oz = 1 cup helps when scaling drink recipes for larger batches.
Frequently Asked Questions
How many ounces are in a cup?
There are 8 US fluid ounces in 1 US customary cup. For dry ingredients, the weight in ounces varies by ingredient density.
How many ounces are in half a cup?
There are 4 fluid ounces in half a cup. Half a cup also equals 8 tablespoons or approximately 118 milliliters.
Is a fluid ounce the same as a weight ounce?
No. A fluid ounce measures volume (29.57 ml), while a weight ounce measures mass (28.35 g). They are only approximately equal for water; for other substances, the difference can be significant.
Quick Reference Section
- 1 US cup = 8 fluid ounces = 16 tablespoons = 236.6 ml
- 1/2 cup = 4 fl oz = 8 tbsp = 118.3 ml
- 1/4 cup = 2 fl oz = 4 tbsp = 59.1 ml
- Key distinction: Fluid ounces measure volume; weight ounces measure mass
For any volume or cooking conversion, use our free cooking converter.