Cups to Oz Converter
Enter a volume in cups and get the result in US fluid ounces, Imperial fluid ounces, or weight ounces for any ingredient. Switch between US and Imperial cups, pick your ingredient for density-accurate weight conversions, or run the calculation in reverse by entering ounces and reading off the cup count. Every result comes with a step-by-step breakdown of the math.
How many ounces are in a cup?
One US cup equals exactly 8 US fluid ounces. That relationship is fixed by definition: the US cup is defined as exactly 8 US fluid ounces, which is 236.588 mL. The Imperial cup used in older British and Commonwealth recipes is larger: it equals 10 Imperial fluid ounces, or about 284.1 mL. If a recipe uses Imperial cups, you need about 20% more volume than a US cup would give you. This calculator handles both and shows you the difference at a glance.
Fluid ounces vs weight ounces - which do you need?
Fluid ounces (fl oz) measure volume. Weight ounces (oz wt) measure mass. The two are different things and are only equal for water by coincidence at near-room temperature: 1 US fl oz of water weighs almost exactly 1 oz. For everything else the numbers differ, often significantly. One cup of all-purpose flour has a volume of 8 US fl oz but weighs only about 4.2 oz because flour is much less dense than water. One cup of honey has 8 fl oz of volume but weighs about 11.9 oz because honey is denser than water. Use fluid ounces when you are measuring with cups or a measuring jug. Use weight ounces when your recipe specifies a mass or when you want the best accuracy, especially in baking.
Why ingredients weigh different amounts per cup
Volume measurements tell you how much space a substance fills, not how much it weighs. The link between the two is density. Water sits at 1 gram per mL, so 236.6 mL weighs 236.6 g (about 8.35 oz). Vegetable oil is slightly lighter (density about 0.92 g/mL), so a cup weighs roughly 7.7 oz. All-purpose flour is much lighter (about 0.53 g/mL when lightly spooned), so a cup weighs only around 4.4 oz. The same logic applies to sugar, oats, cocoa, and every other dry ingredient. Because measuring cups are volume tools, two people can measure a "cup" of flour and get different weights if one packs the cup tightly. A kitchen scale eliminates that variability entirely.
Quick cooking conversions
A US cup breaks down into 16 US tablespoons, 48 US teaspoons, or 8 US fluid ounces. Half a cup is 4 fl oz or 8 tablespoons. A quarter cup is 2 fl oz or 4 tablespoons. These ratios hold for all liquid ingredients. For dry ingredients the tablespoon counts are the same because tablespoons are also volume units, but the weight in ounces changes with density. This calculator shows all three secondary units, tablespoons, teaspoons and mL, alongside the primary ounce result so you can pick the most convenient measure for what you are doing.
Common cups-to-oz conversions (US fluid ounces)
| Cups | US fl oz | Imperial fl oz | mL | Tablespoons | Teaspoons |
|---|---|---|---|---|---|
| 1/8 cup | 1 | 1.2 | 29.6 | 2 | 6 |
| 1/4 cup | 2 | 2.5 | 59.1 | 4 | 12 |
| 1/3 cup | 2.67 | 3.3 | 78.9 | 5.3 | 16 |
| 1/2 cup | 4 | 5.0 | 118.3 | 8 | 24 |
| 2/3 cup | 5.33 | 6.6 | 157.7 | 10.7 | 32 |
| 3/4 cup | 6 | 7.5 | 177.4 | 12 | 36 |
| 1 cup | 8 | 10.0 | 236.6 | 16 | 48 |
| 1.5 cups | 12 | 15.0 | 354.9 | 24 | 72 |
| 2 cups | 16 | 20.0 | 473.2 | 32 | 96 |
| 3 cups | 24 | 30.0 | 709.8 | 48 | 144 |
| 4 cups | 32 | 40.0 | 946.4 | 64 | 192 |
Fluid ounce values are exact US definitions. Weight ounce values use water density (1 g/mL).
Frequently asked questions
How many ounces is 1 cup?
1 US cup equals exactly 8 US fluid ounces. If you are using Imperial cups (common in older British recipes), 1 Imperial cup equals 10 Imperial fluid ounces. For weight, 1 cup of water weighs about 8.35 oz; other ingredients vary because of their different densities.
How many ounces is 1/2 cup?
Half a US cup is exactly 4 US fluid ounces or about 118.3 mL. In tablespoons, that is 8 tablespoons or 24 teaspoons. If you need the weight, 1/2 cup of water is about 4.17 oz, but 1/2 cup of flour is only about 2.1 oz (weight) because flour is much less dense.
What is the difference between fluid ounces and weight ounces?
Fluid ounces (fl oz) are a volume unit - they tell you how much space a liquid fills. Weight ounces (oz) are a mass unit - they tell you how heavy something is. They happen to be close for water, but differ significantly for other substances. Flour, for example, fills 8 fl oz of space in one cup but weighs only about 4.2 oz on a scale because it is much less dense than water.
How do I convert cups to ounces for flour?
Select "Weight ounces" as the output unit, then choose "All-purpose flour" as the ingredient. The calculator applies flours density (about 0.529 g/mL for lightly spooned flour) to give you the weight in ounces. As a rough guide: 1 cup of all-purpose flour weighs about 4.2-4.5 oz (120-128 g), but this varies with how tightly you pack the cup, so a kitchen scale is always more accurate for baking.
How many cups is 16 oz?
16 US fluid ounces equals exactly 2 US cups. For weight ounces, the answer depends on the ingredient: 16 oz of water is about 1.9 cups, 16 oz of flour is about 3.6 cups, and 16 oz of sugar is about 2.2 cups. Use the reverse mode in this calculator, enter 16, select "Weight ounces", and pick your ingredient for the exact answer.
Does this calculator work for dry ingredients?
Yes. Select "Weight ounces" as the output unit and choose the ingredient from the dropdown. The calculator uses that ingredients density to convert the cup volume into a mass. Keep in mind that the exact weight of a dry ingredient per cup depends on how it is scooped: lightly spooned flour weighs less than packed flour. The densities used here are for lightly measured, standard culinary technique.
What is an Imperial cup and how does it differ from a US cup?
An Imperial cup equals 10 Imperial fluid ounces or about 284.1 mL. A US cup is 8 US fluid ounces or about 236.6 mL. The Imperial cup is about 20% larger. Imperial cups appear in older British, Australian and Canadian recipes. Modern Australian and Canadian recipes now use the metric cup (250 mL), which sits between the two. If you are following a recipe and the cup size is unclear, check when and where it was published.