Cups to mL

Baking an American Recipe in a Metric Kitchen

You have printed a recipe from an American blog, and every wet ingredient is written in cups. Your kitchen has a litre jug marked in millilitres, a set of scales and no cup measures at all. Before you pour anything you need the millilitre figure — and you need to know which cup the author had in mind, because at least five different cups are in daily use around the world.

Conversion factor: 1 US customary cup = 236.5882365 mL, so multiply cups by 236.588. A recipe calling for ¾ cup of buttermilk is 0.75 × 236.588 = 177.44 mL — pour to just under the 180 mL line on the jug.

What Sits Behind the Word "Cup"

The cup an American author assumes

Unless a US recipe says otherwise it means the customary cup: half a US pint, eight US fluid ounces, 236.5882365 mL. Every nested measuring set sold in the States is built on it.

The cup on the side of the carton

Nutrition panels use the FDA's legal cup of exactly 240 mL, chosen as a round number for serving sizes. That is why the carton and the cookbook quietly disagree by about 3.4 mL.

Cups that travelled and changed

Australia and New Zealand standardised on a 250 mL metric cup; older British books use a 284 mL imperial cup of ten imperial fluid ounces; Japanese recipes work in a 200 mL cup.

Dry ingredients break the rule

Converting a cup of milk to millilitres is exact. A cup of flour is not really a volume question — how tightly it is packed changes the mass by a fifth, which is why serious bakers reach for scales.

Turning a Recipe Line Into a Jug Reading

Work down the ingredient list once and convert every wet measure before you start, so you are not doing arithmetic with buttery hands halfway through.

Enter the cup amount as a decimal

Fractions become decimals: ¼ is 0.25, ⅓ is 0.333, ½ is 0.5, ⅔ is 0.667, ¾ is 0.75. Type it in the left field and the millilitre figure appears as you type. A comma works instead of a dot, and stray spaces are ignored.

Round to a graduation you can actually see

A jug marked every 25 mL will never show you 177.44 mL. Aim between the marks and accept a millilitre or two of error on liquids — it is far smaller than the error hiding in a heaped scoop of anything dry.

Drop to spoons for the small amounts

For anything under a quarter cup, open the searchable unit list on the right and pick tablespoons or teaspoons instead of millilitres. Vanilla and baking powder are easier to trust on a spoon than at the bottom of a big jug.

Reverse it when the recipe is already metric

Press the swap button (↔) to run the pair backwards, millilitres in and cups out. By hand, divide millilitres by 236.588: a 500 mL carton of cream is 2.11 cups. The copy button hands over the bare number for a note or a spreadsheet.

Check the author's country first. A recipe from Sydney and a recipe from Seattle can both say "1 cup" and mean amounts 13.4 mL apart. Across four cups of liquid that gap grows past 50 mL — enough to loosen a batter noticeably.

The Five Cups You Will Meet in Recipes

Each of these is a real, defined measure still printed in cookbooks today. The right-hand column shows how far each one drifts from the American customary cup that most online recipes assume.

Cup standard	Where it appears	Volume	vs US customary
US customary cup	American cookbooks, recipe sites, measuring sets	236.59 mL	baseline
US legal cup	Nutrition labels and FDA serving sizes	240 mL	+1.4%
Metric cup	Australia, New Zealand, modern metric recipes	250 mL	+5.7%
Imperial cup	Older British and Commonwealth books (10 imp fl oz)	284.13 mL	+20.1%
Japanese cup	Japanese recipes (the rice-cooker gō is 180 mL)	200 mL	−15.5%

Once you know which cup you are reading, the fraction ladder does the rest. These six amounts carry most American recipes from start to finish.

Recipe says	US customary cup	Pour to
¼ cup	59.15 mL	just under 60 mL
⅓ cup	78.86 mL	a shade under 80 mL
½ cup	118.29 mL	about 118 mL
⅔ cup	157.73 mL	just under 160 mL
¾ cup	177.44 mL	a shade under 180 mL
1 cup	236.59 mL	between 235 and 240 mL

What Helps When You Convert a Whole Ingredient List

Both boxes stay live down the ingredient list

Type over the cup figure for each ingredient in turn and the millilitre value refreshes immediately — nothing to clear, no button to press between lines.

Flip direction when a metric recipe lands

The ↔ button reverses the pair so millilitres go in and cups come out, which is what you want the day a European recipe meets an American cup set.

Spoons, ounces and litres in the same dropdown

Both unit lists are searchable and hold every volume unit, so the same page turns cups into tablespoons, US fluid ounces or litres without leaving it.

Clean numbers for your rewritten recipe card

The copy button on each field puts the plain number on the clipboard with no unit attached, ready to paste into the metric version you are typing up.

Questions About Cup Sizes in Recipes

Which cup does an American recipe actually mean?

The US customary cup, 236.5882365 mL. It is defined as half a US liquid pint or eight US fluid ounces, and it is what every measuring set sold in an American supermarket holds. Recipes almost never say so, because to the author there is only one kind of cup.

Why does the carton in my fridge say a cup is 240 mL?

Nutrition labelling in the United States uses a separate "legal" cup fixed at exactly 240 mL so that serving sizes come out as tidy numbers. It is 1.4% larger than the cup your recipe means — 3.41 mL per cup. No cake ever noticed, but it explains why two printed sources hand you different figures for the same word.

Do dry measuring cups and liquid jugs hold the same amount?

Yes — a cup is a cup either way. The difference is how you fill them. Dry cups are made to be levelled flush with a knife, which you cannot do in a jug with a spout and a gap above the top mark. Jugs are made to be read at eye level with the liquid settled, which you cannot do with flour. The error comes from using the wrong vessel, not from the volume.

Why do bakers weigh flour instead of measuring it in cups?

Because a cup of flour has no fixed mass. Scooped straight from the bag it compacts; spooned in gently and levelled it stays loose. The same cup can hold roughly 120 g to 150 g depending on how it was filled — a swing of a fifth in the most important ingredient in the recipe. Millilitres settle the liquids; only grams settle the flour.

My recipe was written with metric cups but I own an American set — what now?

Multiply the metric cups by 250 to get millilitres, then work that back through your own set: one metric cup is 250 mL, or 1.06 US cups. In practice, add about a tablespoon for every American cup you measure. For a single cup of stock in a soup you can ignore it; for four cups of milk in a custard you would be 53.6 mL short, and it will show.