Cups to ounces converter, fluid ounces, exactly.

To convert cups to ounces, multiply the cups by 8. One US cup holds 8 US fluid ounces, so 2 cups is 16 fl oz, 1 1/2 cups is 12 fl oz and a half cup is 4 fl oz. This page gives fluid ounces, which measure volume. An ounce on a kitchen scale measures weight, and a cup of one ingredient weighs a different amount from a cup of another, so no single weight answer exists. The section on weight below says what to do instead.

How to use the converter

1. Type the amount in the US cups (cup) box. Fractions work: 1/3, 3/4, or a mixed number such as 2 1/2.
2. The big result shows US fluid ounces (fl oz). The cards under it give milliliters, tablespoons, teaspoons, pints and quarts for the same amount.
3. Type fluid ounces in the second box to go the other way, or open the Ounces to cups page.
4. Click a row in Common values to load it, or use the arrow keys to add one cup at a time.
5. Press Copy result or Copy link to keep the answer, Copy table for the whole list, or Print chart for a sheet for the kitchen wall.

Why a cup is 8 ounces

NIST Handbook 44 (2026), Appendix C lists the measuring cup as "8 fluid ounces (exactly)" and as half a liquid pint, and gives 237 milliliters for it. The fluid ounce itself comes from the gallon: 231 cubic inches divided into 128 parts, which is 29.5735 mL each. Eight of them make 236.588 mL, which the table rounds to 237. Page checked 19 Oct 2026.

US nutrition labels use a rounded cup. 21 CFR 101.9(b)(5)(viii) says that for labelling a cup means 240 mL and 1 fl oz means 30 mL. The ratio is still 240 ÷ 30 = 8, so both systems agree on 8 ounces to a cup. What differs is the size of the ounce and the cup, not the count. Checked 19 Oct 2026.

Fluid ounces are not weight ounces

The word ounce names two units. A fluid ounce is a measure of space. An ounce in the avoirdupois system is a measure of weight, 28.349523125 grams according to Handbook 44. A cup of flour, a cup of honey and a cup of water all hold 8 fluid ounces, and they do not weigh the same, so this page does not try to give "8 oz of flour in cups". That would need the density of the food, and a number made up for the sake of a tidy answer would be wrong for your flour.

Two safe ways out. If the recipe gives grams or weight ounces, weigh the food. The Ounces to grams and Grams to ounces pages convert weights exactly. If the recipe gives cups, measure with a cup. The label rule above also says 1 oz in weight means 28 g on a nutrition label, a rounded figure for labels only.

Worked examples

• 1 1/2 cups of milk. 1.5 × 8 = 12 fl oz, or 24 tablespoons.
• 2 1/2 cups of stock. 2.5 × 8 = 20 fl oz, which is 1.25 pints.
• 1/3 cup of oil. 8 ÷ 3 = 2.6667 fl oz. In spoons that is 5.3333 tablespoons, or 5 tbsp + 1 tsp.
• 4 cups of water. 4 × 8 = 32 fl oz, which is exactly one US quart.
• 12 cups of soup for a crowd. 12 × 8 = 96 fl oz, which is 3 quarts, or 3/4 of a gallon.

Cup fractions in fluid ounces

Every row is exact for the US system. The milliliter column is rounded to one decimal.

Three different cups

If a recipe was written for another cup, the count of 8 still holds but the volume does not. One cup of each kind, measured in US fluid ounces:

The gap between the first and the last is 5.67 percent. In a cake that shows. No official page fixes the 250 mL cup, so the converter treats it only as a card, never as a fact about cups.

Mistakes to avoid

The first is reading "8 oz" on a package as 1 cup. Package weights are in weight ounces unless the label says fl oz, so a bag marked 8 oz is a weight, not a cup. The second is a UK recipe. The UK fluid ounce is about 28.41 mL, and Handbook 44 puts it at 0.961 of a US fluid ounce, about 4 percent smaller than the US one, so UK amounts in fl oz come out a bit lower in cups. The third is copying a rounded figure such as 237 mL into a long calculation. Use the exact ratio instead and round once at the end, which the Decimals setting does.

Need the other direction in more detail? The Ounces to cups page starts from fluid ounces. For smaller measures see Cups to tablespoons and Cups to teaspoons. For bigger ones, Gallons to ounces.