Fluid Oz to Cups Converter
8 fl oz × 0.125 = 1 cups
As a fraction: 1 cups
There are 8 US fluid oz in 1 US cup, so to convert fluid oz to cups you divide by 8. That means 4 fl oz is 1/2 cup, 2 fl oz is 1/4 cup, 12 fl oz is 1.5 cups, and 16 fl oz is 2 cups (1 US pint). Type any number of fluid oz into the converter above and it returns the answer in cups, rounded to the kitchen fractions you actually measure with: 1/4, 1/3, 1/2, 2/3 and 3/4.
One caution before you use the number. The 8-to-1 rule applies to FLUID oz, a measure of volume. It does not apply to oz of weight. Eight weight oz of flour is roughly 1.8 cups, not 1 cup, because flour is far lighter than water for the same space. If your recipe lists a dry ingredient in oz, read the dry-versus-fluid section below before you reach for a measuring cup.
How many oz are in a cup?
A US cup holds 8 US fluid oz. In metric terms, that cup is 236.588 mL, and each US fluid oz is 29.5735 mL. Those two numbers are the whole tool: 8 × 29.5735 mL gives you the 236.588 mL cup. Half a cup is 4 fl oz (118.29 mL), a quarter cup is 2 fl oz (59.15 mL), and a third of a cup is about 2.67 fl oz (78.86 mL).
Going the other way, multiply cups by 8. That gives 12 fl oz (355 mL) for 1.5 cups, which is why a soda can says 12 fl oz; 16 fl oz (473 mL) for 2 cups, one US pint; 32 fl oz (946 mL) for 4 cups, one US quart; and 128 fl oz (3.79 L) for 16 cups, one US gallon.
The formula
cups = fluid oz ÷ 8, and fluid oz = cups × 8. Because 8 divides cleanly into the fractions cooks use, most answers land on a familiar mark: 2 fl oz is exactly 1/4 cup, 4 fl oz is exactly 1/2 cup, 6 fl oz is exactly 3/4 cup. Only the thirds do not divide evenly, 1/3 cup is 2.67 fl oz (78.86 mL) and 2/3 cup is 5.33 fl oz (157.7 mL).
- Confirm the recipe means FLUID oz (a liquid, or a volume measurement). If it lists a dry ingredient in oz, that is weight, weigh it instead.
- Divide the number of fluid oz by 8. Example: 6 fl oz ÷ 8 = 0.75 cup.
- Round the decimal to the nearest kitchen fraction: 0.75 becomes 3/4 cup. The converter above does this step for you.
What is a fluid oz?
A fluid oz is a unit of volume, the amount of space a liquid occupies. The US fluid oz is defined as 29.5735 mL. It is written fl oz, and the "fl" is the part that matters, because it separates the unit from the oz of weight (28.3495 g) that shares its name and its abbreviation in casual writing.
The UK imperial fluid oz is a slightly different size: 28.4131 mL, about 4 percent smaller than the US one. On drink labels and in older British recipes an imperial pint is 20 fl oz, while a US pint is 16 fl oz. This converter uses the US fluid oz, which is the one nearly all recipes written in cups assume.
What is a cup?
A cup is a cooking volume unit, and its size depends on where the recipe was written. The US customary cup is 8 US fl oz, or 236.588 mL. The metric cup used in Australia and New Zealand is a round 250 mL, about 5.6 percent larger. The imperial cup found in older British texts is 284.13 mL, about 20 percent larger than the US cup.
For most cooking, the 5 percent gap between a US cup and a metric cup will not ruin a dish. Baking is less forgiving: follow an Australian recipe with US cups and the shortfall compounds across four or five measurements, leaving a batter noticeably dry. Check which cup a recipe means before you scale it.
Dry oz vs fluid oz: the trap that ruins recipes
Only 8 FLUID oz make 1 cup. Eight WEIGHT oz of flour is roughly 1.8 cups. The two words look the same on a page and are abbreviated the same way, but they measure different things: a fluid oz measures how much space something takes up, and a weight oz (28.3495 g) measures how heavy it is. A US cup of water weighs about 236 g. A US cup of all-purpose flour weighs about 120 g, because flour is far less dense, it is mostly air and loosely packed particles. Same cup, half the weight.
Run the numbers and the size of the error becomes obvious. Eight weight oz of flour is 227 g. At about 120 g per cup, that is roughly 1.8 cups. So a baker who reads "8 oz flour" and measures out 1 cup is using barely half the flour the recipe called for. The dough will be soupy, and no amount of extra baking time will fix it. The same mismatch runs the other way for dense ingredients: 8 oz of honey is well under a cup, because honey weighs about 340 g per cup.
Water is the one place the two nearly coincide, 8 fl oz of water weighs almost exactly 8 oz, and that coincidence is exactly why the confusion survives. It works for water, so people assume it works for everything. It does not. The rule to carry into the kitchen is simple: if a recipe lists a DRY ingredient in oz, that is weight, and the cup conversion on this page does not apply. Put it on a scale. If a recipe lists a liquid in oz, that is almost always fluid oz, and dividing by 8 gives you the cups you need.
Fluid oz to cups conversion table
Based on the US cup: 8 US fl oz = 1 cup = 236.588 mL. Values are shown as the kitchen fractions you can actually measure. Thirds are not exact, 1/3 cup is 2.67 fl oz.
| Fluid oz (US) | Cups (US) |
|---|---|
| 2 | 0.25 |
| 4 | 0.5 |
| 6 | 0.75 |
| 8 | 1 |
| 10 | 1.25 |
| 12 | 1.5 |
| 14 | 1.75 |
| 16 | 2 |
| 20 | 2.5 |
| 32 | 4 |
1 fl oz = 0.125 cups
Popular fluid oz and cup conversions
Frequently asked questions
There are 8 US fluid oz in 1 US cup, which is 236.588 mL. To convert any number of fluid oz to cups, divide by 8. To go from cups to fluid oz, multiply by 8.
No. 8 weight oz of flour is roughly 1.8 cups, not 1 cup. A US cup of all-purpose flour weighs about 120 g (4.2 oz), so 8 oz of flour (227 g) fills nearly two cups. Only 8 FLUID oz equals 1 cup. When a recipe says "8 oz flour" it means weight, use a scale.
Half a US cup is 4 fl oz (118.29 mL). A quarter cup is 2 fl oz (59.15 mL), and three quarters of a cup is 6 fl oz (177.44 mL).
No. A US cup is 236.588 mL (8 US fl oz). The metric cup used in Australia and New Zealand is 250 mL, about 5.6 percent larger. The imperial cup in older UK recipes is 284.13 mL, about 20 percent larger. This converter uses the US cup.
Because a coffee "cup" is not a measuring cup. Coffee makers use a 5 fl oz (148 mL) serving as their cup, so a 12-cup carafe holds about 60 fl oz (1.77 L), not 96 fl oz. Japanese rice cookers use a different cup again, about 6 fl oz. Only the 8 fl oz measuring cup applies to recipes.
Not accurately. Liquid measuring cups are jugs with a spout and headroom, read at eye level against a line. Dry measuring cups are filled to the brim and levelled off with a straight edge. Scooping flour with a liquid jug typically overpacks it and can add 20 percent or more to the amount, because you cannot level the top.
1/3 US cup is about 2.67 fl oz (78.86 mL), and 2/3 cup is about 5.33 fl oz (157.7 mL). Thirds are the only common kitchen fractions that do not divide evenly into fluid oz, so measuring cups marked in thirds are more reliable than counting oz.
2 US cups is 16 fl oz (473.18 mL), which is exactly 1 US pint. 4 cups is 32 fl oz (946.35 mL), or 1 US quart, and 16 cups is 128 fl oz (3.79 L), or 1 US gallon.
By weight, yes, but that is a coincidence of butter's density, not the fluid-oz rule. A US cup of butter weighs about 227 g (8 oz), which is two US sticks. Butter is one of the few common ingredients where the weight in oz and the fluid-oz volume land close together, which is why butter wrappers can be marked in both.
Yes. Fluid oz measure volume, so 8 fl oz of water, milk, oil, honey or juice all fill exactly 1 US cup. The weight of those cups differs a lot, a cup of oil weighs about 218 g and a cup of honey about 340 g, but the volume is identical.