How Many Ounces Are in a Cup?
Quick Answer: 8 fluid ounces in 1 US cup · 237 mL · 16 tablespoons
At a glance
- 1 US cup = 8 fluid ounces (fl oz) (volume — what recipes mean)
- 8 fl oz = 237 mL = 16 tablespoons (same volume, different units)
- 8 oz by weight only equals a cup for water (flour is ~4¼ oz, butter ~8 oz, sugar ~7 oz per cup)
A US cup holds 8 fluid ounces. That's the answer if you're measuring liquid, and it's what every US recipe means when it says "1 cup". The catch: "ounce" in cooking means two different things. Fluid ounces measure volume — the space the ingredient takes up. Ounces (plain "oz") usually measure weight. They only match when the ingredient weighs the same as water, and almost nothing does. A cup of flour weighs about 4¼ oz. A cup of feathers (if you could cram them in) would weigh almost nothing. The number on your measuring cup is always volume.
How many fluid ounces in 1 cup?
cup → fl oz Quick Converter
Need more features? Try our complete cup to fluid ounce converter.
1 cup on the fluid-ounce scale
1 cup = 8 fl oz
Ounces by weight: how much does a cup of each ingredient weigh?
Fluid ounces and weight ounces share a name but measure different things. One cup always equals 8 fluid ounces. The weight of that cup depends entirely on what's in it. Here's the actual weight for common ingredients — the numbers your kitchen scale will show.
| Ingredient (1 US cup) | Weight (oz) | Weight (g) | Quick note |
|---|---|---|---|
| Water | 8 oz | 237 g | The one ingredient where 1 cup = 8 oz matches by weight |
| Milk (whole) | 8.6 oz | 244 g | Slightly heavier than water |
| Butter (melted or soft) | 8 oz | 227 g | Two sticks — by happy coincidence also 8 oz by weight |
| Vegetable oil | 7.7 oz | 218 g | Lighter than water |
| Granulated sugar | 7 oz | 200 g | Dense and packs well |
| Brown sugar (packed) | 7.5 oz | 213 g | "Packed" matters — unpacked is ~5 oz |
| All-purpose flour | 4¼ oz | 120 g | Spoon-and-level method — scooping adds 20% |
| Bread flour | 4.5 oz | 128 g | Slightly heavier than AP |
| Confectioners' sugar | 4 oz | 113 g | Very light, sift before measuring |
| Shredded cheese | ~3 oz | ~85 g | Varies by cheese and shred size; mozzarella and cheddar are close |
| Rolled oats | 3 oz | 85 g | Lots of air — very light per cup |
| Rice (long-grain, uncooked) | 6.5 oz | 185 g | Cooked rice weighs 2–3× more per cup |
Need weight conversions across cup fractions, or an ingredient not on this list? Use our Cooking Volume to Weight converter — it covers hundreds of ingredients at any fraction.
Fluid ounce vs weight ounce — the biggest mistake in US recipes
- Fluid ounce (fl oz) — a unit of volume. 1 cup = 8 fl oz always. This is what measuring cups measure.
- Ounce (oz) — a unit of weight. 1 cup of flour weighs about 4¼ oz, 1 cup of water 8 oz, 1 cup of honey about 12 oz. This is what your kitchen scale measures.
Recipes written in the US almost always mean fl oz when they say "oz" in a liquid context ("6 oz of milk") and weight oz when they say "oz" for solid ingredients ("8 oz of cream cheese"). If the recipe has a weight range that seems too small to be volume — "2 oz of parmesan" — it's weight. If the liquid quantity lines up neatly with cup fractions — "4 oz of milk" = ½ cup — it's volume. The context tells you which one.
Did you know?
A cup of coffee
in a coffee maker isn't 8 fl oz — it's 5 or 6. That's why a 12-cup
drip machine makes a carafe that holds only about 60 fl oz of coffee, not 96. The smaller coffee cup dates back to when ceramic mugs were smaller, and the industry kept the convention. If your recipe calls for a cup of coffee as an ingredient, it means a kitchen cup (8 fl oz), not a coffee-maker cup.
How many cups in a fluid ounce?
1/8 cup (0.125 cup). A fluid ounce is the basic building block of US cooking volume. Handy conversions in the other direction:
- 4 fl oz = ½ cup
- 6 fl oz = ¾ cup (standard coffee-maker "cup")
- 8 fl oz = 1 cup
- 12 fl oz = 1½ cups (a soda can)
- 16 fl oz = 2 cups = 1 US pint (a standard water bottle)
How many ounces in half a cup?
Half a US cup = 4 fluid ounces. Also 118 mL, 8 tablespoons, or 24 teaspoons. By weight, a half-cup depends on the ingredient: 2 oz of flour, 4 oz of water, 3.5 oz of sugar, 1.5 oz of shredded cheese. If you only own a 1-cup measure, fill it to the ½-cup line on the side — don't guess.
How many ounces in a 1/4 cup?
A quarter cup = 2 fluid ounces. Also 4 tablespoons, 12 teaspoons, or about 59 mL. A 1/4 cup is the smallest in a standard US measuring-cup set. It's a convenient multiple: a ¾ cup is three of them, a ½ cup is two, a full cup is four.
Common cup amounts in fluid ounces
| Amount | Fluid ounces | Also useful |
|---|---|---|
| ¼ cup | 2 fl oz | 4 tbsp · 59 mL |
| ⅓ cup | ~2.67 fl oz | 5 tbsp + 1 tsp · 79 mL |
| ½ cup | 4 fl oz | 8 tbsp · 118 mL |
| ⅔ cup | ~5.33 fl oz | 10 tbsp + 2 tsp · 158 mL |
| ¾ cup | 6 fl oz | 12 tbsp · 177 mL |
| 1 cup | 8 fl oz | 16 tbsp · 237 mL |
| 1½ cups | 12 fl oz | 24 tbsp · 355 mL |
| 2 cups | 16 fl oz | 1 US pint · 473 mL |
Word order matters
- "How many half-cups in a cup?" → 2 (two half-cup scoops make a cup)
- "How many ounces in a half cup?" → 4 fl oz (the volume of that half-cup scoop)
Same words, different order, completely different answer. Always read the direction first.
The formula
fluid ounces = cups × 8
Or in metric: mL = cups × 236.588
The US customary cup is defined as 8 fluid ounces by construction — that's the whole point of the unit. The derivation goes: 1 US fl oz = 1.8046875 cubic inches ≈ 29.5735 mL, and 8 × that = 236.588 mL, which is the US customary cup. Everything else in the US kitchen measurement system (pints, quarts, gallons) is built on the same 8-fl-oz-per-cup skeleton.
Cup to ounce conversion table
mL values are NIST-exact, rounded to 1 decimal.
| Cups | Fluid ounces | Tablespoons | Milliliters |
|---|---|---|---|
| ⅛ cup | 1 fl oz | 2 tbsp | 29.6 |
| ¼ cup | 2 fl oz | 4 tbsp | 59.1 |
| ⅓ cup | ~2.67 fl oz | 5⅓ tbsp | 78.9 |
| ½ cup | 4 fl oz | 8 tbsp | 118.3 |
| ⅔ cup | ~5.33 fl oz | 10⅔ tbsp | 157.7 |
| ¾ cup | 6 fl oz | 12 tbsp | 177.4 |
| 1 cup | 8 fl oz | 16 tbsp | 236.6 |
| 1¼ cups | 10 fl oz | 20 tbsp | 295.7 |
| 1½ cups | 12 fl oz | 24 tbsp | 354.9 |
| 1¾ cups | 14 fl oz | 28 tbsp | 414.0 |
| 2 cups | 16 fl oz | 32 tbsp | 473.2 |
| 3 cups | 24 fl oz | 48 tbsp | 709.8 |
| 4 cups | 32 fl oz | 64 tbsp | 946.4 |
Need an arbitrary value? Use the full cup to fluid ounce converter or the extended conversion table.
What about UK or Imperial cups?
The old Imperial cup holds 10 Imperial fluid ounces, which is about 9.6 US fluid ounces — roughly 20% bigger than a US cup. Imperial fluid ounces are themselves slightly smaller than US fl oz (28.4 mL vs 29.57 mL), so the Imperial cup ends up at 284 mL total. Modern UK recipes almost never use cups; they measure in grams and millilitres. If you're reading a vintage British cookbook and it says "1 cup", add about 20% to your US-cup measure to get close. If it's a modern UK recipe, ignore cups entirely — weigh it.
How to measure a cup accurately
Liquid ingredients
Use a glass measuring cup, put it on a flat surface, and bring your eye down to the level of the fill line. Read the flat part of the liquid (the meniscus), not the edge that climbs the wall. Tilting the cup up to your eye will make you under-pour by a full tablespoon easily.
Dry ingredients by volume
Use nested dry measuring cups. Spoon the ingredient into the cup until it mounds over, then level the top with the straight edge of a knife. Don't scoop directly into flour — it packs the flour and adds up to 20% more weight. For baking, where 20% matters, switch to a kitchen scale.
Why a scale beats a cup for baking
Professional bakers and the King Arthur test kitchen both work in grams for a reason: a cup of flour measured by weight is always 120 g, while a cup measured by scoop can run anywhere from 120 to 160 g. That 40 g swing is the difference between tender cookies and hockey pucks. If the recipe gives grams alongside cups, use the grams. A decent scale costs less than one bad batch of cookies.
Frequently Asked Questions
How many ounces are in 1 cup?
One US cup holds 8 fluid ounces (fl oz) — that's the volume. It's also about 237 mL. If your recipe asks for ounces by weight, though, the answer changes with every ingredient: 1 cup of water weighs 8 oz, but 1 cup of flour weighs only about 4¼ oz. See the table below.
Is 1 cup the same as 8 oz?
For liquids in US recipes, yes — 1 cup = 8 fluid ounces. For dry ingredients measured by weight, no. A cup of flour weighs ~4¼ oz, a cup of shredded cheese ~3 oz, a cup of sugar ~7 oz. The "8 oz = 1 cup" shortcut only works when the ingredient has roughly the density of water.
How many ounces in half a cup?
4 fluid ounces — half of 8 fl oz. That's also 118 mL or 8 tablespoons. By weight, a half-cup varies by ingredient (2 oz of flour, 4 oz of butter, 4 oz of water).
How many ounces in a 1/4 cup?
2 fluid ounces. Also 4 tablespoons, 12 teaspoons, or about 59 mL. A 1/4 cup is the smallest of the standard US measuring-cup set.
How many oz in a cup of water?
A cup of water is 8 fl oz by volume AND 8 oz by weight — this is the one ingredient where the two numbers match, because water has a density of 1 g/mL. That's where the "8 oz = 1 cup" rule of thumb comes from. It doesn't hold for anything else.
How many ounces of flour in a cup?
About 4¼ oz (120 g) for all-purpose flour, if you spoon it into the cup and level it off. Scooping directly packs the flour and pushes the weight toward 5 oz — a 20% difference that wrecks baking. For weight-based flour conversions across cup fractions, use our Cooking Volume to Weight converter.
How many ounces in an Imperial (UK) cup?
The Imperial cup is about 9.6 US fluid ounces (or 10 Imperial fl oz) — bigger than a US cup. Modern UK recipes rarely use cups at all, though; they measure in grams and millilitres. If a pre-1970s British cookbook calls for "a cup", assume 284 mL (about 9.6 US fl oz).
How many half-cups in a cup, vs how many oz in a half cup?
Word order changes the answer. Half-cups in a cup = 2 (two half-cup scoops make a cup). Ounces in a half cup = 4 fl oz (the volume of that half-cup scoop). Same words reversed, completely different answer.
How many cups in a fluid ounce?
1/8 cup (0.125 cup). A fluid ounce is the building block — 8 of them make a cup, 16 make a pint, 32 make a quart, 128 make a gallon.
Related Cooking Conversions
- How many mL in a cup? — 240 mL (US legal)
- How many tablespoons in a cup? — 16 tbsp
- How many cups in a pint? — 2 cups
- How many cups in a quart? — 4 cups
- How many ounces in a pint? — 16 fl oz
- How many ounces in a quart? — 32 fl oz
- How many teaspoons in a tablespoon? — 3 tsp
- How many mL in an ounce? — 29.57 mL
- How many ounces in a tablespoon? — 0.5 fl oz
- How many ounces in a shot? — 1.5 fl oz
- How many teaspoons in a cup? — 48 tsp
- How many ounces in a pound? — 16 oz (weight, not volume)
- How many grams in an ounce? — 28.35 g (weight ounce)
- Cooking Volume to Weight Converter — "How much does 1 cup of flour weigh?"
- Cooking Weight to Volume Converter — "Convert 8 oz butter to cups"
- All Cooking Measurement Tools
This page answers the US-recipe meaning of "ounce in a cup" — fluid ounces, a volume unit, where 1 cup always equals 8 fl oz. Weight-ounces (oz) depend on the ingredient's density and are covered in the weight table above plus our dedicated volume-to-weight and weight-to-volume converters. The Imperial (UK) cup is mentioned for historical reference; modern UK recipes use grams and millilitres.