Enter a US cup amount to find its US fluid ounces, or calculate an ingredient's weight using its known one-cup weight.
Advanced options
Table of contents
How to use our Cups to Ounces Converter
- Choose "US fluid ounces" for a volume conversion, or choose "Ingredient weight (oz)" if you need the weight of a specific ingredient.
- Enter the amount from your US recipe as a decimal, fraction, or mixed number, such as 1.5, 1/2, or 1 1/2.
- For ingredient weight, enter the ingredient name and its weight for 1 US cup from the package, recipe, or a trusted ingredient reference.
- Select "Calculate." For a quick check, 1 US cup should equal 8 US fl oz in the fluid-volume setting.
Definitions
US customary cup: A US cooking unit of volume. One US cup equals 8 US fluid ounces. [1]
US fluid ounce (US fl oz): A unit of volume used for liquids and other measured volumes.
Ounce by weight: A unit of mass used by kitchen scales. Different ingredients can have different weights for the same cup volume.
Mixed number: A whole number plus a fraction, such as 1 1/2 cups.
Gram (g): A metric unit of mass. The ingredient-weight calculation also shows the weight in grams.
Common mistakes and quick fixes
Mistake: Entering a metric cup or another non-US cup amount.
Fix: Check Convert cups to and then recalculate. Convert the source amount to US cups first. This calculator treats every cup entered as a US customary cup.
Mistake: Reading US fluid ounces as ounces by weight.
Fix: Use US fluid ounces for volume. Choose "Ingredient weight (oz)" only when you have a one-cup weight for that ingredient.
Mistake: Typing an unclear recipe amount such as 1//2.
Fix: Check Convert cups to and then recalculate. Enter one decimal, simple fraction, or mixed number, such as 0.5, 1/2, or 1 1/2.
Mistake: Using 8 oz per cup as an ingredient's weight because a cup equals 8 fluid ounces.
Fix: Check Convert cups to and then recalculate. Copy the ingredient's actual weight for 1 US cup. Fluid ounces measure volume, while ingredient ounces measure weight.
Mistake: Using a one-cup weight for a different preparation, such as packed instead of sifted.
Fix: Check Convert cups to and then recalculate. Match the ingredient and preparation words in the source of the one-cup weight.
Limitations & Key Assumptions / Boundary Conditions
- The cup input is a US customary cup. It does not convert metric cups or other non-US cup definitions automatically.
- The US fluid-ounce answer is a volume measurement, not an ingredient weight.
- Ingredient-weight results depend entirely on the one-cup weight entered. Brand, moisture, packing, sifting, chopping, and other preparation details can change that weight.
- The entered one-cup weight must match both the named ingredient and its preparation method.
- Displayed results are rounded to the selected number of decimal places, while the calculation uses the unrounded value.
Methodology
Fluid-volume calculation
The fluid-volume path multiplies the entered US cup amount by 8. One US customary cup equals 8 US fluid ounces. [1]
US fluid ounces = US cups x 8
For example, 1.5 US cups x 8 = 12 US fl oz.
Ingredient-weight calculation
A cup does not have one fixed weight for every ingredient, so this path uses the weight for 1 US cup that you enter. It multiplies that weight by the entered cup amount.
Ingredient weight (oz) = US cups x entered weight of 1 cup (oz)
The unrounded ounce weight is then multiplied by 28.349523125 to convert it to grams.
Ingredient weight (g) = ingredient weight (oz) x 28.349523125
For example, 2 cups x 4.25 oz per cup = 8.5 oz. Then 8.5 x 28.349523125 = 240.9709465625 g before display rounding.