US cups to millilitres Converter

How many millilitres are in a US cup?

One US cup is 236.588236 millilitres. The full conversion is millilitres = US cups × 236.5882365, and going the other way you divide instead of multiply.

A few anchor values worth memorising: 236.588236 ml to the US cup, 2,365.882365 ml to ten, and 23,658.82365 ml to a hundred. The calculator above handles the rest, including the awkward decimals.

The reference table under the converter lists the values people look up most often, so for a common figure you can read the answer off directly rather than typing anything.

Worked examples

Three worked examples, each multiplying by 236.5882365:

2.5 cup × 236.588236 = 591.4706 ml. 25 cup × 236.588236 = 5,914.7059 ml. 250 cup × 236.588236 = 59,147.0591 ml.

To reverse any of them, divide instead of multiplying — or use the swap button above, which does the same thing without the arithmetic. Reversing a converted value should return you to exactly what you started with; if it does not, something has been rounded too early.

Doing this conversion in your head

The exact factor is 236.5882365, which nobody multiplies by in their head. It is very close to 2839/12, so multiplying by 2839 and dividing by 12 lands within 0% of the correct answer — accurate enough for anything short of engineering work.

Since the factor is greater than one, the number always gets bigger: a US cup is smaller than a millilitre, so any quantity converts to more of them. If your answer came out smaller, you have divided when you should have multiplied.

That sanity check catches the majority of real conversion errors. Before trusting any converted figure, ask whether the direction of change makes sense — it takes a second and it is the single most effective safeguard there is.

When you need to convert US cups to millilitres

There are a handful of recurring contexts where a US cup figure has to be restated in millilitres.

On the source side, cups are the standard measure in American recipes and baking. On the target side, millilitres are medicine doses, recipe liquids and drink container sizes. The conversion is essentially a translation between those two worlds — most often because a figure produced in one context has to be understood, submitted or acted on in the other.

Where the converted figure will be cut, dosed, billed or filed, round once at the end rather than at each step. For a rough sense of scale, round freely.

None of this leaves your browser. The conversion is a few lines of arithmetic, so there is no server involved and nothing to store.

What a US cup and a millilitre actually are

The US cup (cup). The US legal cup is 240 ml, the customary cup 236.6 ml, and a metric cup 250 ml.

The millilitre (ml). Equal to one cubic centimetre — the unit of medicine doses and recipes.

Because both measure volume and their definitions are set by standards bodies, the factor between them never changes. It is not an approximation that improves with better instruments; it is a definition.

Common mistakes when converting US cups to millilitres

Watch out for the US/imperial split. The US gallon is 3.785 litres and the imperial gallon is 4.546 litres — about 20% larger. The fluid ounces differ too: 29.57 ml in the US against 28.41 ml in the UK. This converter uses US customary units, which is what almost all recipes published online assume.

Cups are worse still, because there are three in circulation: the US customary cup at 236.6 ml, the US legal cup at 240 ml used on nutrition labels, and the metric cup at 250 ml used in Australia and New Zealand. For baking, where ratios matter, weighing ingredients in grams sidesteps the whole problem.

For a batch of figures, set the units once and work down the list rather than converting via a third unit — each intermediate step introduces its own rounding.