What is a cup, and what is a liter?
A cup is a unit of volume used in kitchens. A liter is a unit of volume used almost everywhere else. Converting cups to liters is one multiplication — the catch is that "cup" isn't one unit. It's four, and they disagree by up to 20%.
The liter
A liter is exactly 1,000 cubic centimeters, or 1,000 millilitres. It's the metric unit for liquid volume, so it's what a jug in a European kitchen is marked in, what a bottle of milk is sold in outside the US, and what a scientific paper will use. A liter of water weighs one kilogram at room temperature, which is the reason the unit exists in that size. Below a liter, millilitres are the number you actually pour, so the Cups to Liters Converter shows both.
The cup — and why there are four of them
The cup came out of American home cooking, where volume beat weight because a measuring set is cheaper than a scale. Then other countries adopted the word without adopting the size.
| Which cup | Exactly | Where you'll meet it |
|---|---|---|
| US customary | 0.2365882365 L (236.5882 mL) | American recipes, American measuring sets |
| Metric | 0.25 L (250 mL) | Australia, New Zealand, Canada, modern UK books |
| US legal ("label") | 0.24 L (240 mL) | Nutrition labels on US packaging |
| UK imperial | 0.284130625 L (284.1306 mL) | Older British recipes and cookbooks |
The US customary cup is one sixteenth of a US gallon. The UK imperial cup is one sixteenth of an imperial gallon, which is a bigger gallon — hence the 20% gap between the two. The metric cup is a round 250 mL because round numbers were the point. The legal cup is 240 mL so the servings printed on the back of a packet come out tidy.
How cups to liters conversion works
Multiply. That's the whole operation.
liters = cups × 0.2365882365 — for US customary cups. Use 0.25 for metric cups, 0.24 for US label cups, and 0.284130625 for UK imperial cups.
Those four constants are exact definitions, not measurements, so the conversion has no error in it. The only rounding is in how the answer gets displayed.
Take ¾ cup, which is the sort of amount a recipe actually asks for. Type 3/4 and the Cups to Liters Converter reads it as 0.75 cups, then shows the calculation it ran: 0.75 cups × 0.2365882365 = 0.177441 L. Underneath, that's 177.4412 mL. In a jug, pour 175 mL.
Two cups is the other one everybody looks up. Two US cups is 0.473176 L — 473.1765 mL, so 475 mL in practice. Two metric cups is a flat 0.5 L. The 27 mL between those two answers is a little under two US tablespoons: invisible in a pot of stock, noticeable in a cake batter, and a real problem once you scale the recipe up.
The reason the Cups to Liters Converter reads your number as US customary by default is that this is the direction where the input is ambiguous. You copied "2 cups" off a recipe and the recipe didn't say whose cup it meant. So the headline answer uses the American cup — the dominant case, and the cup in a standard measuring set — and the other three readings sit on the line below it, unasked-for and there anyway.
Common cups-to-liters conversions
Every value below comes straight out of the Cups to Liters Converter, including the display precision. The last column is what to do at the counter.
| Cups | US → L | US → mL | Metric → L | In the kitchen, pour |
|---|---|---|---|---|
| ¼ cup | 0.059147 | 59.1471 | 0.0625 | 60 mL |
| ⅓ cup | 0.078863 | 78.8627 | 0.083333 | 80 mL |
| ½ cup | 0.118294 | 118.2941 | 0.125 | 120 mL |
| ¾ cup | 0.177441 | 177.4412 | 0.1875 | 175 mL |
| 1 cup | 0.236588 | 236.5882 | 0.25 | 235 mL |
| 1½ cups | 0.354882 | 354.8824 | 0.375 | 355 mL |
| 2 cups (1 US pint) | 0.473176 | 473.1765 | 0.5 | 475 mL |
| 3 cups | 0.709765 | 709.7647 | 0.75 | 710 mL |
| 4 cups (1 US quart) | 0.946353 | 946.3529 | 1 | 945 mL |
| 6 cups | 1.4195 | 1,419.5294 | 1.5 | 1.42 L |
| 8 cups (½ US gallon) | 1.8927 | 1,892.7059 | 2 | 1.9 L |
| 16 cups (1 US gallon) | 3.7854 | 3,785.4118 | 4 | 3.79 L |
Two patterns are worth pulling out of that table. The first: 4 US cups is not a liter. It's 0.946353 L, about 54 mL short — roughly a quarter-cup missing. It is exactly a liter in metric cups, which is the entire reason the metric cup was set at 250 mL, and it's also exactly one US liquid quart. Three different true statements about "4 cups," which is how the confusion starts.
The second: the US column is a check on itself. 4 cups comes out as 0.946352946 L, the defined size of a US liquid quart. 16 cups comes out as 3.785411784 L, the defined US gallon. Neither is special-cased in the converter — they fall out of the multiplication, which is a decent sign the constant is right.
The mental version: a US cup is just under a quarter of a liter. Take a quarter and shave 5% off. So 4 cups is a bit under a liter, 8 cups a bit under two. Going the other way, one liter is 4.2268 US cups. For metric cups there's nothing to memorize — divide by 4.
When you'll need to convert cups to liters
Cooking an American recipe in a metric kitchen. This is most of the traffic to this page. You have a measuring jug marked in millilitres and a recipe written in cups, and you'd like the soup to happen tonight. Convert once, write the millilitres in the margin, cook.
Scaling a batch. Doubling is fine in cups. Multiplying by ten is where the 5% error between cup definitions turns into a visible mistake. Assume 4 cups is a liter, scale to 40 cups, and you're 0.536 L short of the 10 L you thought you had — over half a liter of missing liquid, in a dough that will tell you about it.
Buying by the bottle. A recipe wants 8 cups of stock. That's 1.9 L, so the 2 L carton covers it and the 1 L one doesn't. Volume conversion is mostly a shopping question.
Writing a recipe for both audiences. If you publish, you need both numbers, and you need to say which cup you meant. "2 cups (475 mL)" ends the argument in the comments.
Unit conversion is arithmetic that's been settled by treaty since 1959, which makes it a strange thing to put behind a login. Plenty of measurement pages ask for an email before they'll multiply by a constant, or fold the conversion into a recipe manager with a per-seat price and a trial clock that starts the moment you land. Some hide the decimals until you upgrade. This page is the multiply. It runs in your browser, nothing is sent to a server, there's no account, and there's no tier of it you don't have. That's the full tool.
Edge cases and gotchas
Fractions work, because recipes use them. Measuring sets are labelled ¼, ⅓, ½, ¾ — so 3/4, 1 1/2, ¾, 1½ and 2 1/4 cups all read correctly. You don't have to convert to a decimal first.
Typing another unit gets you a nudge, not a wrong answer. Enter "2 liters" or "6 tbsp" and the Cups to Liters Converter says it takes cups instead of quietly treating your 2 as two cups. If you're starting from tablespoons, the tablespoons to cups converter is the first step; from fluid ounces, use oz to cups.
Commas are read the American way. "1,250" is taken as one thousand two hundred fifty, and you get a note saying so — because in much of Europe that string means 1.25, and silently picking one reading would be worse than mentioning it.
The decimals are display, not noise. Under one liter you get six decimal places, at one liter and above you get four. That's why ½ cup reads 0.118294 rather than a rounded 0.12: the math keeps the exact constant so scaling stays honest, and only the screen rounds. Very large volumes print as whole liters with comma separators instead of flipping to scientific notation.
Volume isn't weight. A cup of water is 237 g; a cup of all-purpose flour is about 125 g. If your recipe wants grams, no volume converter can get you there without knowing the ingredient — that's what the cups to grams converter is for.
Related converters
Going the other direction — a metric recipe, an American measuring set — is mL to cups. For the bigger US volumes, quarts to liters and liters to gallons cover the same math one step up the ladder, and every US volume unit is a doubling of the one below it: 1 cup = 8 fl oz, 2 cups = 1 pint, 4 cups = 1 quart, 16 cups = 1 gallon.
If you're converting a whole recipe rather than one line of it, the cooking measurement converter handles cups, spoons, ounces and grams together. And when the ingredient is dry and the target is a scale, cups to grams asks which ingredient — because it has to.
Frequently asked questions
How many liters are in a cup?
A US customary cup is exactly 0.2365882365 L — call it 0.237 L, or 236.6 mL. A metric cup is exactly 0.25 L. A US nutrition-label cup is 0.24 L, and a UK imperial cup is 0.284130625 L. Multiply your cups by whichever one matches the recipe you're reading. Most of the time that's the first.
Is 4 cups exactly 1 liter?
Not in US cups. Four US cups is 0.946353 L, so you're about 54 mL short of a liter — roughly a quarter-cup. It is exactly a liter in metric cups. This is the error that bites when you scale: assume 4 cups is a liter, multiply by ten, and you're missing over half a liter.
Why does this show four different answers?
Because "cup" is four units, and here the ambiguity is in what you typed rather than what you get back. Printing a single number would mean guessing which cup your recipe meant and being up to 20% wrong. Showing all four costs you one glance and removes the guess.
My recipe says 2 cups of stock. How much is that in metric?
473.1765 mL — pour 475 mL and nobody will ever know. That's if the recipe is American. If it's Australian or from a modern British book, 2 metric cups is a round 500 mL instead.
Can I type ¾ or 1 1/2 instead of a decimal?
Yes. "3/4", "1 1/2", "¾", "1½" and "2 1/4 cups" all read correctly. Typing 3/4 gives 0.177441 L, the same as typing 0.75, because that's what the converter turns it into first.
Does this work for flour and other dry ingredients?
It converts the volume, which is correct for anything you measure by scooping. But a cup of flour and a cup of water hold very different weights, so if the recipe wants grams, volume-to-volume won't get you there. Use cups to grams, which asks for the ingredient.
What does it cost, and is what I type stored?
Nothing, and no. The conversion runs in your browser — nothing goes to a server, nothing is saved, closing the tab clears it. There's no sign-up and no cap on how many conversions you run. Microapp is funded by membership and ads, and 10% of every dollar it earns goes to charity, off the top, audited quarterly.