What this calculator does
A US cup is defined as exactly 8 US fluid ounces, which makes oz to cups one of the cleanest conversions in the kitchen: divide by 8 to go from ounces to cups, multiply by 8 to go the other way. It comes up constantly when a recipe is written in one unit and your measuring gear is marked in the other.
This calculator converts fluid ounces to cups or cups to fluid ounces, in either direction, and also shows the equivalent in millilitres and in 250 mL metric cups, the size used in most Australian and British recipes. Fluid ounces measure volume, not weight, which is worth keeping in mind: 4 oz to cups or 6 oz to cups only works cleanly for liquids, since a cup of flour and a cup of water do not weigh the same.
The formula
A US cup equals exactly 8 US fluid ounces. To convert fluid ounces to cups, divide by 8. To convert cups to fluid ounces, multiply by 8. The millilitre figure comes from the standard US fluid ounce, 29.5735 mL, and the metric cup figure divides that millilitre total by 250, the size of a metric cup used outside the US.
| Term | Meaning |
|---|---|
| Fluid ounce (fl oz) | A US unit of volume, exactly 1/8 of a US cup, or 29.5735 mL. |
| Cup (US) | A standard US volume measure equal to exactly 8 fl oz, or 236.588 mL. |
| Metric cup | A 250 mL cup used in Australian, British and New Zealand recipes, slightly larger than a US cup. |
The inputs explained
| Field | What to enter |
|---|---|
| Convert | Choose from Fluid ounces to cups, Cups to fluid ounces. |
| Amount | The amount to convert, in fluid ounces if converting to cups, or in cups if converting to fluid ounces. |
When to use it
Converting a US recipe to cup measures
US recipes sometimes list liquid ingredients in fluid ounces rather than cups; dividing by 8 turns 16 oz to cups (2 cups) or 14 oz to cups (1.75 cups) without reaching for a calculator mid-recipe.
Checking a container size
Packaging often states a fluid ounce volume; converting it to cups shows at a glance how many cup measures it will fill, useful when doubling or halving a recipe.
Working between US and metric kitchens
A US cup (236.6 mL) and a metric cup (250 mL) are close but not identical, so a recipe written for one and measured with the other drifts slightly; the metric cup figure here flags that difference.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How many cups are common fluid ounce amounts?
A range of fluid ounce amounts converted to cups, including the common 4 oz, 6 oz, 14 oz and 16 oz figures.
| Fluid ounces | Cups | In millilitres |
|---|---|---|
| 2 fl oz | 0.2500 cups | 59.1 mL |
| 4 fl oz | 0.5000 cups | 118.3 mL |
| 6 fl oz | 0.7500 cups | 177.4 mL |
| 8 fl oz | 1.000 cups | 236.6 mL |
| 14 fl oz | 1.750 cups | 414.0 mL |
| 16 fl oz | 2.000 cups | 473.2 mL |
How many fluid ounces are common cup amounts?
A range of cup amounts converted to fluid ounces.
| Cups | Fluid ounces | In millilitres |
|---|---|---|
| 0.25 cups | 2.00 fl oz (US) | 59.1 mL |
| 0.5 cups | 4.00 fl oz (US) | 118.3 mL |
| 0.75 cups | 6.00 fl oz (US) | 177.4 mL |
| 1 cups | 8.00 fl oz (US) | 236.6 mL |
| 1.5 cups | 12.00 fl oz (US) | 354.9 mL |
| 2 cups | 16.00 fl oz (US) | 473.2 mL |
Questions
Is 8 oz always exactly 1 cup?
Yes, for a US fluid ounce and a US cup: a US cup is defined as exactly 8 US fluid ounces, so 8 oz to cups is always exactly 1 cup. This does not hold for a UK/Imperial fluid ounce, which is a slightly smaller unit.
Does this work for dry ingredients like flour or sugar?
Fluid ounces and cups are both volume measures, so the ratio (8 fl oz per cup) still holds for volume. What changes is the weight: a cup of flour and a cup of water have very different weights, so a recipe stating a dry ingredient by weight needs a weight-based conversion instead.
Why does a metric cup differ from a US cup?
A US cup is 236.588 mL by definition, while a metric cup, used in Australia, the UK and New Zealand, is a rounder 250 mL. The difference is small, about 5.6%, but it can shift a recipe measured with the wrong cup size if the recipe relies on several cups of a liquid ingredient.
How many cups is 100ml?
About 0.42 US cups, since 100 mL divided by 236.588 mL comes to roughly 0.423. For millilitre-to-cup conversions specifically, the cup to mL converter handles any mL amount directly.
For a conversion starting from millilitres rather than fluid ounces, see the cup to mL converter. For fluid ounces converted to millilitres directly, use the ounces to mL converter.