How many ounces are in a cup? Liquid and dry measurements explained

Quick cup-to-fluid-ounce chart

In US recipes, cups and fluid ounces both measure volume. Multiply cups by 8 to find US fluid ounces, or divide fluid ounces by 8 to find cups.

The most common fractions are easy to remember: one-quarter cup is 2 fluid ounces, one-half cup is 4 fluid ounces, and three-quarters cup is 6 fluid ounces.

• 1/8 cup = 1 US fluid ounce
• 1/4 cup = 2 US fluid ounces
• 1/3 cup = about 2.67 US fluid ounces
• 1/2 cup = 4 US fluid ounces
• 3/4 cup = 6 US fluid ounces
• 1 cup = 8 US fluid ounces
• 2 cups = 16 US fluid ounces, or 1 US pint

Fluid ounces and weight ounces are different

A fluid ounce measures volume—the space a liquid occupies. An ounce without the word fluid usually measures weight. The two units answer different questions, so 1 cup does not automatically weigh 8 ounces.

Water is close to 8.35 ounces by weight per US cup, while flour is much lighter and dense ingredients can be heavier. To convert a cup of a specific food to weight, use a reliable ingredient-by-weight chart or weigh it on a kitchen scale.

• Use fl oz for liquid volume.
• Use oz or grams for ingredient weight.
• Do not convert cups to weight ounces without identifying the ingredient.

Tablespoons, teaspoons and milliliters

The USDA's measurement table gives 16 tablespoons or 48 teaspoons in 1 US cup. That means 2 tablespoons equal 1 fluid ounce and 3 teaspoons equal 1 tablespoon.

NIST uses 240 milliliters as the practical metric equivalent of a US cup for cooking. The exact US customary cup is about 236.6 milliliters, but 240 milliliters is the standard rounded kitchen conversion used in US nutrition labeling and many recipes.

US, Imperial and metric cups are not identical

A recipe's country matters. A US customary cup is about 236.6 milliliters. An Australian, Canadian, or other metric recipe may use a 250-milliliter cup. Older British recipes may use an Imperial cup of about 284 milliliters.

The fluid-ounce unit also changes between systems. A US fluid ounce is about 29.57 milliliters, while an Imperial fluid ounce is about 28.41 milliliters. For an international recipe, milliliters or grams usually remove the ambiguity.

• US customary cup: about 236.6 mL
• US kitchen and nutrition-label equivalent: 240 mL
• Metric cup: 250 mL
• Imperial cup: about 284 mL

How to measure a cup accurately

For liquids, place a liquid measuring cup on a level surface and read the line at eye level. For dry ingredients, fill the correct dry cup and level the top without packing unless the recipe specifically says to pack it.

For baking, a digital scale is often more consistent because flour can settle or become compressed. If a recipe supplies gram measurements, use them instead of converting the ingredient back to cups.

• Use a spouted liquid cup for water, milk and oil.
• Use level dry cups for flour, sugar and similar ingredients.
• Follow instructions such as sifted, packed or chopped before measuring.
• Use the recipe author's unit system when it is stated.

Examples

A recipe calling for 1.5 US cups of milk needs 12 US fluid ounces because 1.5 multiplied by 8 equals 12. A 20-fluid-ounce container holds 2.5 US cups because 20 divided by 8 equals 2.5.

For 2/3 cup, multiply two-thirds by 8 to get about 5.33 fluid ounces. In practical kitchen measures, that is 10 tablespoons plus 2 teaspoons.

Sources

Primary and official references used for this guide:

• NIST Metric Kitchen: cooking measurement equivalencies
• USDA Agricultural Research Service: measurement conversion tables
• NIH NIGMS: How Many Ounces Are in a Cup?