Cups to Ounces Converter

What this does

So your recipe is in cups, but your kitchen scale or a food label talks in ounces, and you want the weight. This converter does that. Enter your cups, tell it which ingredient you are measuring, pick your cup size, and it gives you the weight in ounces. The ingredient matters here, because a cup of one thing weighs a very different amount from a cup of another.

How to use it

1. Enter the number of cups.
2. Choose the ingredient from the list.
3. Pick your cup size, US Legal (240 ml) or Imperial (284 ml).
4. Leave the unit on Ounces for a weight in ounces, then press Calculate.

For weighing out an ingredient, Ounces is the option you want.

Why the ingredient matters

A cup measures volume, the space something fills, while an ounce of weight measures how heavy it is. To get from one to the other you need the ingredient's density, which is just how much it weighs for its size. And that varies a lot.

A US Legal cup of water weighs about 8.5 ounces. The same cup of flour weighs far less, because flour is light and airy, while a cup of honey weighs more, because it is dense. That is why the tool asks for the ingredient before it does the sum. Flour is the wobbliest of the lot: depending on how you scoop and pack it, a cup can swing by a fair margin, so treat any flour figure as a good guide rather than a hard number, and weigh it when a recipe really depends on it.

Ounces versus fluid ounces

This is the trap worth knowing. An ounce (oz) is a weight. A fluid ounce (fl oz) is a volume. They share a name, which causes endless confusion, but they only line up for water. For anything else they are different numbers.

Here is the key idea: a cup holds the same number of fluid ounces no matter what is in it, because that is fixed by the cup's size. A US Legal cup is about 8.1 US fluid ounces whether it is filled with flour, honey, or water. Weight is the part that changes with the ingredient. So when you want to know how heavy your ingredient is, stay on Ounces, the weight option. Fluid ounces answer a different question, which is how much space it takes up.

How the conversion works

Under the hood, the tool works out the weight in grams from your cups and the ingredient's density, then turns grams into ounces. One ounce is 28.3495 grams, so:

ounces = grams ÷ 28.3495

So a US Legal cup of water, which is about 240 grams, comes to 240 ÷ 28.3495, or roughly 8.47 ounces. A lighter ingredient in the same cup lands lower, a denser one higher.

Questions people ask

References

1. King Arthur Baking. Ingredient Weight Chart. https://www.kingarthurbaking.com/learn/ingredient-weight-chart
2. National Institute of Standards and Technology. Handbook 44, Appendix C: General Tables of Units of Measurement. https://www.nist.gov/document/nist-hb-44-2024-appendix-c-general-tables-units-measurement