Cups to Oz Converter
Fluid ounces by volume, or ounces by weight for any ingredient.
- Cups—
- Millilitres—
- Grams—
- Tablespoons—
- Teaspoons—
- Pounds—
The one thing to get right first
There are two completely different things called an ounce, and mixing them up is why so many recipes go wrong.
- A fluid ounce measures volume — how much space something takes up. One US cup is always 8 fluid ounces, for water, flour, feathers or lead. It never changes.
- An ounce measures weight. One cup of water weighs about 8.3 oz, but one cup of flour weighs only about 4.4 oz. The volume is identical; the weight is nearly half.
So “how many ounces in a cup” has two answers. If the recipe means volume, it is 8, always. If it means weight, it depends entirely on what you are measuring, which is why the ingredient selector above matters.
A quick way to tell which a recipe means: liquids are nearly always given in fluid ounces, while dry ingredients given in ounces almost always mean weight. If a recipe says “8 oz flour”, it wants you to use scales.
How to use this converter
- Enter the amount and the unit it is written in. You can start from cups, spoons, millilitres or from a weight.
- Pick the ingredient, which sets the density used for all weight conversions.
- Choose the cup standard if you are not using an American recipe. They genuinely differ.
Cups are not the same everywhere
| Cup standard | Millilitres | US fluid ounces | Where used |
|---|---|---|---|
| US customary | 236.6 ml | 8.00 | American recipes |
| US legal | 240 ml | 8.12 | US nutrition labels |
| Metric | 250 ml | 8.45 | Australia, NZ, Canada |
| UK imperial | 284.1 ml | 9.61 | Older British recipes |
| Japanese | 200 ml | 6.76 | Japanese recipes |
An Australian cup holds about six percent more than an American one, and an old British imperial cup holds twenty percent more. For a sauce that hardly matters. For bread or cake, where the flour to liquid ratio decides the result, it matters a great deal.
Common conversions by weight
One US cup of each, which is where the big differences show up:
| Ingredient | Grams | Ounces (weight) | Fluid ounces |
|---|---|---|---|
| Water | 237 g | 8.35 oz | 8 fl oz |
| Flour, all purpose | 125 g | 4.41 oz | 8 fl oz |
| Sugar, granulated | 200 g | 7.05 oz | 8 fl oz |
| Sugar, brown (packed) | 220 g | 7.76 oz | 8 fl oz |
| Butter | 227 g | 8.00 oz | 8 fl oz |
| Honey | 340 g | 11.99 oz | 8 fl oz |
| Rolled oats | 90 g | 3.17 oz | 8 fl oz |
| Cocoa powder | 85 g | 3.00 oz | 8 fl oz |
Look down that fluid ounce column: every single one is 8. Now look at the weights, which run from 85 g to 340 g. A cup of honey weighs four times what a cup of oats weighs. That single comparison is the whole argument for the ingredient selector.
Spoons and smaller measures
1 tablespoon = 3 teaspoons = 0.5 fl oz
1 fl oz = 2 tablespoons
These hold for US measures. Australian tablespoons are 20 ml rather than 15, holding four teaspoons instead of three, which quietly throws out any recipe using baking powder or yeast.
Why bakers weigh instead
Professional bakers use scales, and the reason is flour. How much fits in a cup depends on whether it was scooped or spooned, whether it was sifted, and how firmly it settled in the bag. The same cup can hold anywhere from 120 g to 150 g, a swing of twenty-five percent.
Scales remove the question. 125 g of flour is 125 g regardless of technique. If a recipe matters to you, weighing it is the single biggest improvement you can make, and it means fewer measuring cups to wash.
If you are stuck with cups, the method that comes closest to the standard 125 g is to stir the flour in its container, spoon it loosely into the cup, and level the top with a knife. Never scoop the cup through the bag, which compacts the flour and can add thirty grams without you noticing.
Where this gets confusing
- Butter in sticks. American recipes often call for sticks. One stick is half a cup, 8 tablespoons, 113 g or 4 oz by weight.
- Coffee cups. A coffee maker’s “cup” is usually 5 or 6 fl oz, not 8. A twelve-cup pot does not hold twelve measuring cups.
- Canned goods. A tin labelled 15 oz is giving weight, not volume.
- Nutrition labels. US labels use the 240 ml legal cup, which is slightly larger than the cup in the recipe book beside it.
Frequently asked questions
How many ounces are in a cup?
It depends which ounce you mean. One US cup is always 8 fluid ounces by volume. By weight the answer changes with the ingredient: a cup of water weighs about 8.35 oz, but a cup of flour weighs only about 4.4 oz.
Is a fluid ounce the same as an ounce?
No. A fluid ounce measures volume, the space something occupies. An ounce measures weight. They happen to be close for water, which is why they are confused, but for flour, oats or honey they are very different.
How many ounces is a cup of flour?
About 4.4 ounces by weight, or 125 grams. By volume it is still 8 fluid ounces, like any other cup. Flour is light for its bulk, which is why its weight is roughly half that of water.
How many grams are in a cup?
It depends on the ingredient. A cup of water is about 237 g, flour about 125 g, granulated sugar about 200 g, butter about 227 g and honey about 340 g. Volume stays the same while weight varies with density.
Are American and Australian cups the same?
No. A US customary cup is 236.6 ml while an Australian metric cup is 250 ml, about six percent larger. An old UK imperial cup is 284 ml, twenty percent larger again. Choose the right standard in the converter.
How many tablespoons are in a cup?
Sixteen US tablespoons make one US cup, and each tablespoon is three teaspoons, so a cup is 48 teaspoons. Note that an Australian tablespoon is 20 ml and holds four teaspoons.
Why do bakers weigh ingredients instead of using cups?
Because a cup of flour can hold anywhere from 120 to 150 grams depending on how it was scooped and settled, a swing of about twenty-five percent. Weighing removes that variation entirely and gives repeatable results.
How much is one stick of butter?
One US stick of butter is half a cup, 8 tablespoons, 4 ounces by weight or about 113 grams.