How Many Ounces in a Cup?

To take the guesswork out of cooking conversions, we've created this simple guide. For quick conversions, reference the table below for how many ounces in a cup.
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A glass measuring cup for fluid ounces and cups filled with non-dairy milk.
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Have you ever been knee-deep in a new recipe when you suddenly realize there’s a discrepancy in measurements, so now you’re asking, how many ounces are in a cup? Neither are foreign, but when you need to switch between the two, it’s like speaking different languages that don’t intersect.

Don’t worry, it’s a common question and one we can easily answer! Once you learn the trick, you’ll be able to quickly calculate the exact amounts even if you’re not exactly a math pro.

What Are Ounces?

The word “ounce” comes from the Latin “uncia,” which is the name for both the Roman ounce and inch units (weight and length.) The abbreviation of “oz” comes from the Italian and Spanish translation, “onza.” For reference, one ounce is roughly equal to the weight of a slice of wholegrain bread, a new wooden pencil, or one AA battery.

It’s essential to remember that fluid ounces are measured differently from dry ounces; fluid ounces are used for volume measurements, while dry ounces are used for weight measurements. When we’re converting for cups, we’re talking about volume which are fluid ounces.

What Are Cups?

Cups began as literal cups pulled from kitchen cabinets, ranging in size from teacups to wine glasses. There was no uniformity to this approach which led to wildly inconsistent results, especially in baked goods that demand more exacting ratios of ingredients. American cookbook author Fanny Farmer is credited with popularizing a standardized, uniform measuring cup in the late 1800s.

Cups can be used to measure the volume of both dry and wet ingredients. There are some designed more like pitchers specifically for use with liquids, but both can be used interchangeably in a pinch.

A half cup measure filled with plant-based milk.

How Many Ounces In A Cup?

Since packaged foods often express serving sizes in ounces, it’s incredibly helpful to know what that means in terms of cups. Next time, you won’t need to break out the actual cups to decode what that means for your individual portion, because the conversion is very easy.

8 ounces (fl oz) = 1 US cup (c)

That makes equivalent conversations a snap. Here are other common measurements in case you need a cheat sheet:

Fluid OuncesCups
2 ounces¼ cup
4 ounces½ cup
6 ounces¾ cup
8 ounces1 cup

What’s The Difference Between Fluid Ounces and Ounces?

Ounces can sometimes be used to express weight measurements, but don’t get it confused: fluid ounces don’t necessarily equal plain ounces. For example, 8 ounces of water is still 8 fluid ounces of water, but molasses is denser, so 1.6 ounces of molasses by volume equals 1.3 US fluid ounces by weight.

What Are Troy Ounces?

This standard of measurement is still used in precious metals today, but it is unlikely to be found in the kitchen. It’s an antiquated expression of weight that dates back to the Middle Ages. 1 troy ounce is equal to 1.097 standard ounces, or 0.137125 US cups. I’d rather not have to measure that out, personally!

More Quick Cooking Conversions

We hope you found this easy conversion guide useful for understanding how to convert ounces to cups! This article was written with support from Hannah Kaminsky and edited by Rachel Lessenden. Photos by Amanda McGillicuddy for World of Vegan, all rights reserved.

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