Cups to Ounces: The Short Answer
1 cup = 8 fluid ounces = 236.6 mL. That part is fixed and never changes, because it is a volume-to-volume conversion.
The trouble starts the moment a recipe says “ounces” without telling you which kind. There are two:
- Fluid ounces (fl oz) measure volume. One cup of anything — water, flour, honey, gravel — is 8 fl oz.
- Weight ounces (oz) measure mass. One cup of water is 8.3 oz, one cup of all-purpose flour is 4.2 oz, one cup of honey is 12 oz.
So “cups to ounces” has two completely different answers depending on which ounce you mean. This guide covers both, with the number you actually need for each ingredient.
| Cups | Fluid ounces | Tablespoons | Teaspoons | Milliliters |
|---|---|---|---|---|
| 1 cup | 8 fl oz | 16 tbsp | 48 tsp | 236.6 mL |
| ¾ cup | 6 fl oz | 12 tbsp | 36 tsp | 177 mL |
| ⅔ cup | 5.33 fl oz | 10 tbsp + 2 tsp | 32 tsp | 158 mL |
| ½ cup | 4 fl oz | 8 tbsp | 24 tsp | 118 mL |
| ⅓ cup | 2.67 fl oz | 5 tbsp + 1 tsp | 16 tsp | 79 mL |
| ¼ cup | 2 fl oz | 4 tbsp | 12 tsp | 59 mL |
| ⅛ cup | 1 fl oz | 2 tbsp | 6 tsp | 30 mL |
| 1 tbsp | 0.5 fl oz | 1 tbsp | 3 tsp | 14.8 mL |
Bookmark that table, or skip it — our Kitchen Measurement Converter handles cups, fluid ounces, milliliters, grams, and 40+ ingredient densities in one pass.
Weight Ounces per Cup, by Ingredient
This is the table that actually matters when a recipe is written by weight. A cup is a fixed volume; how much it weighs depends entirely on how densely the ingredient packs.
| Ingredient | 1 cup in grams | 1 cup in weight oz |
|---|---|---|
| Water | 237 g | 8.3 oz |
| Milk | 244 g | 8.6 oz |
| Heavy cream | 238 g | 8.4 oz |
| Vegetable oil | 216 g | 7.6 oz |
| All-purpose flour | 120 g | 4.2 oz |
| Bread flour | 127 g | 4.5 oz |
| Whole wheat flour | 120 g | 4.2 oz |
| Granulated sugar | 200 g | 7.1 oz |
| Brown sugar (packed) | 220 g | 7.8 oz |
| Powdered sugar | 120 g | 4.2 oz |
| Butter | 227 g | 8.0 oz |
| Honey | 340 g | 12.0 oz |
| Corn syrup | 328 g | 11.6 oz |
| Cocoa powder | 85 g | 3.0 oz |
| Rolled oats | 90 g | 3.2 oz |
| Chocolate chips | 170 g | 6.0 oz |
| Raw rice (uncooked) | 185 g | 6.5 oz |
| Peanut butter | 258 g | 9.1 oz |
Notice butter is the one ingredient where 1 cup really is exactly 8 ounces by weight — a coincidence of density, not a rule. Flour is barely half that.
Why 1 Cup of Flour Is Not 8 Ounces
Flour has roughly a third of the density of water because the space between the particles is air. Scoop flour straight from the bag with the measuring cup and you compress it, pushing that number from 120 g up to 150 g per cup — a 25% error. That is the difference between a tender cake and a dense brick.
Two habits fix it:
- Spoon and level. Spoon flour into the cup, then sweep the top flat with a knife. Never tap or pack.
- Weigh when the recipe gives grams. If a recipe lists 120 g of flour per cup and you scoop, you are effectively using 1.25 cups. Weights remove the ambiguity entirely, which is why professional formulas almost always use them.
If you bake a lot, run your scaled-up batches through the Recipe Servings Calculator — it rescales flour, sugar, leavening, and liquid together so the ratios survive the multiplication.
Fluid Ounces: US, UK, and Metric Are All Different
This is where most cup-to-ounce confusion lives. A “cup” is not an international unit.
| Cup standard | Volume | US fl oz | UK fl oz |
|---|---|---|---|
| US customary cup | 236.6 mL | 8.0 | 8.3 |
| US legal cup (nutrition labels) | 240 mL | 8.1 | 8.4 |
| Metric cup (Australia, Canada, NZ) | 250 mL | 8.5 | 8.8 |
| UK imperial cup (legacy) | 284.1 mL | 9.6 | 10.0 |
A UK fluid ounce is 28.41 mL; a US fluid ounce is 29.57 mL. They are close enough that most recipes work, but they are not interchangeable, and a UK cookbook using “1 cup” predating metrication is really asking for about 284 mL — a 20% larger pour than a US cup.
Practical rule for modern recipes: assume US cup (236.6 mL) unless the recipe or site is Australian, in which case assume 250 mL. If precision matters, use the Conversion Chart and work in grams.
How to Tell Which Ounce a Recipe Means
Use these signals before you commit:
- “fl oz,” “fluid oz,” or a liquid ingredient → volume. Milk, stock, juice, oil, vanilla.
- “oz” next to a solid, or a package weight → weight. “8 oz cream cheese” is one block, not one cup. “8 oz chocolate chips” is about 1⅓ cups.
- Butter → weight. A stick is 4 oz, so “8 oz butter” is 2 sticks or 1 cup.
- Anything with “drained weight” → weight of the solids only, never a volume.
- Nutrition labels in the US → the US legal cup of 240 mL, which is what the serving size is based on.
When in doubt on a liquid, 8 fl oz of water-like liquid is close enough to 8 oz of weight that the recipe will not notice. When in doubt on a powdery solid, do not guess — convert with grams and skip the argument.
Scaling Cups and Ounces Up and Down
Doubling a recipe is easy in cups (2 cups stay 2 cups) but annoying in ounces (4.2 oz becomes 8.4 oz, which no kitchen scale labels helpfully). Two shortcuts:
- Work in cups, convert once. Scale the cup amounts first, then convert the final total. Fewer rounding errors.
- Switch to grams for anything above 4 cups. 960 g of flour is unambiguous; “8 cups” depends on who scooped it.
Pair it with the Baking Pan Converter when you scale a batter-based recipe — doubling the batter without changing pan size gives you a soggy center, and doubling servings without changing pan depth gives you a spill.
Quick Reference: Common Conversions
- 1 cup water = 8.3 oz = 237 g = 236.6 mL
- 1 cup all-purpose flour = 4.2 oz = 120 g
- 1 cup granulated sugar = 7.1 oz = 200 g
- 1 cup butter = 8.0 oz = 227 g = 2 sticks
- 1 cup honey = 12.0 oz = 340 g
- 1 fl oz = 2 tbsp = 29.57 mL
- 8 fl oz = 1 cup = ½ US pint
- 16 fl oz = 1 US pint = 2 cups
Try Our Free Tools
Stop converting by hand. The Kitchen Measurement Converter turns cups into ounces, grams, and milliliters for any ingredient instantly. For batch work, the Recipe Servings Calculator rescales the whole ingredient list at once, and the Conversion Chart is a printable one-pager for the fridge door. Free, no signup, works offline once loaded.