Ounces to Cups Converter
Choose whether your ounces are a weight or a fluid measure, enter the amount and read the answer in US legal or imperial cups. Weight ounces depend on the ingredient, fluid ounces do not.
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Created by the Reeliy Editorial Team. Last updated: Oct 19, 2026
Ounces and cups in recipes
The word ounce covers more than one thing in a kitchen, and mixing them up is the most common reason for a failed conversion. This converter treats three separate units:
- Ounces (the first option) are a unit of weight, about 28.35 grams. They are what you read from a kitchen scale.
- US fluid ounces are a unit of volume of about 29.57 ml.
- Imp. fluid ounces are a unit of volume of about 28.41 ml, used in the UK.
A cup is a volume. Fluid ounces go straight to cups, but a weight in ounces first has to be turned into a volume, which needs the ingredient's density. That is why the Ingredient menu matters here: 8 ounces of flour fills far more cups than 8 ounces of honey.
How to convert ounces to cups
- If you are converting a weight, pick your ingredient. For fluid ounces you can leave the menu alone.
- Enter the amount and choose Ounces, US Fluid Ounces or Imp. Fluid Ounces as the starting unit.
- Choose US Legal Cups (240 ml) or Imperial Cups (284.13 ml) in the To menu and read the result.
cups = fluid ounces × 29.5735 ÷ 240US fluid ounces to US legal cups. Use 28.4131 and 284.1306 for the imperial pair.
cups = ounces × 28.3495 ÷ (density in g/ml × 240)Weight ounces to US legal cups.
Worked examples
8 ounces of water. 8 oz is 226.8 g, which is 226.8 ml of water. Divided by 240 this is 0.945 cups. It is not a full cup because a cup of water weighs about 8.5 ounces.
8 ounces of flour. At 0.52 g/ml the same 226.8 g takes up 436.2 ml, so it fills 1.817 cups, almost double the water figure.
8 ounces of runny honey. Honey is dense (1.4 g/ml), so 226.8 g is only 162 ml, or 0.675 cups.
8 US fluid ounces. No ingredient is needed: 8 × 29.5735 = 236.59 ml, so you get 0.986 US legal cups.
16 imperial fluid ounces. An imperial cup is ten imperial fluid ounces, so 16 oz is 1.6 imperial cups.
Fluid ounces to cups table
| Fluid ounces | US fl oz → US legal cups | Imp. fl oz → imperial cups |
|---|---|---|
| 1 | 0.123 | 0.1 |
| 2 | 0.246 | 0.2 |
| 4 | 0.493 | 0.4 |
| 6 | 0.739 | 0.6 |
| 8 | 0.986 | 0.8 |
| 10 | 1.232 | 1 |
| 12 | 1.479 | 1.2 |
| 16 | 1.972 | 1.6 |
| 20 | 2.464 | 2 |
| 24 | 2.957 | 2.4 |
| 32 | 3.943 | 3.2 |
Weight ounces to cups by ingredient
| Ingredient | 4 oz in cups | 8 oz in cups | 16 oz in cups |
|---|---|---|---|
| Water | 0.472 | 0.945 | 1.89 |
| Flour | 0.909 | 1.817 | 3.635 |
| Caster Sugar | 0.562 | 1.125 | 2.25 |
| Granulated Sugar | 0.528 | 1.056 | 2.112 |
| Icing / Powdered Sugar | 0.762 | 1.524 | 3.048 |
| Brown Sugar | 0.559 | 1.118 | 2.237 |
| Butter | 0.493 | 0.985 | 1.971 |
| Vegetable Oil | 0.515 | 1.029 | 2.059 |
| Milk | 0.456 | 0.911 | 1.823 |
| Runny Honey | 0.337 | 0.675 | 1.35 |
| Rice | 0.591 | 1.181 | 2.362 |
| Cocoa Powder | 1.016 | 2.032 | 4.064 |
The figures assume a typical packing of each ingredient. Sifted flour or loosely spooned sugar will fill more cups than shown, tightly packed brown sugar fewer. For exact baking, weigh instead of measuring by cup.
Common mistakes
- Assuming 8 ounces is a cup. That rule is for fluid ounces. By weight, 8 ounces is a cup only for a liquid that is about as dense as water, and even then it is slightly under (0.945 of a legal cup).
- Mixing US and imperial. An imperial fluid ounce is about 4% smaller than a US one, but an imperial cup is bigger than a US cup.
- Forgetting the ingredient. The same number of ounces on a scale gives different cup counts for flour, sugar and oil.
For the opposite conversion, try the cups to ounces converter.
Frequently asked questions
How many ounces are in a cup?
By volume, a US legal cup is 8.1 US fluid ounces (the traditional US cup is exactly 8). By weight it depends on the ingredient: a cup of water weighs about 8.5 ounces, a cup of flour about 4.4 ounces.
Is 8 oz equal to 1 cup?
Only for fluid ounces, and then it is nearly a cup (0.986 of a US legal cup). For weight, 8 oz of water is 0.945 cups and 8 oz of flour is 1.817 cups.
What is the difference between a US and an imperial fluid ounce?
A US fluid ounce is about 29.57 ml and an imperial fluid ounce about 28.41 ml, so the imperial one is roughly 4% smaller.
Why does the answer change when I choose another ingredient?
Because the ounces are a weight in that case. Heavier ingredients take up less space than lighter ones, so the same weight fills fewer cups.
References
- NIST Special Publication 811, Guide for the Use of the International System of Units (SI)
- U.S. Code of Federal Regulations, 21 CFR 101.9, Nutrition labeling of food (household measures for nutrition labels)
Cite this converter and page
If you use this page in your work, you can cite it as:
Reeliy Editorial Team. (2026). Ounces to Cups Converter. Reeliy. https://reeliy.com/converters/convert-oz-to-cups“Ounces to Cups Converter.” Reeliy, 2026, https://reeliy.com/converters/convert-oz-to-cups.