1 Cup of Milk in Milliliters

One cup of milk is 240 milliliters on the label

One US cup of milk holds 240 mL when the number comes from a nutrition label. The FDA rule for serving sizes states that, for labeling, a cup means 240 mL, a tablespoon means 15 mL and a fluid ounce means 30 mL (21 CFR 101.9(b)(5)(viii), current as of 2026). The same paragraph fixes an ounce of weight at 28 g.

Poured into a glass measuring cup, that same cup holds 236.6 mL. The label rounds up by 3.4 mL so a cup stays at 8 fluid ounces and a tablespoon stays at half a fluid ounce. In fluid ounces one legal cup reads 8.12 fl oz: 240 / 29.5735 = 8.12. Counted in spoons it is 16.2 customary tablespoons, or 16 of the 15 mL label spoons.

Weight is a separate number. FoodData Central record 171265 lists one cup of whole milk at 244 g, which carries 149 kcal, 7.93 g of fat and 7.69 g of protein (USDA SR Legacy, revised April 2019).

The calculator above opens on the legal cup and whole milk, so its first screen matches this paragraph. Switch the standard to the measuring cup and the volume drops to 236.6 mL while the weight stays at 244 g, which is the gap the next two sections explain.

Three cups, three answers: 240, 236.6 and 250 mL

Appendix C of NIST Handbook 44 defines the US gallon as 231 cubic inches, exactly 3.785411784 L (2024 edition). A measuring cup is one sixteenth of that gallon, so 3785.411784 / 16 = 236.6 mL. The table in Appendix C rounds the same figure to 237 mL and describes it as 8 fluid ounces exactly.

The metric cup used in Canadian, Australian and New Zealand cookbooks is 250 mL, a round number with no tie to gallons. Between them sits the FDA cup at 240 mL, a labeling convention rather than a physical measure. Three cups, three numbers, and only one of them is a vessel you can hold.

The gaps look small until a recipe multiplies them. Metric minus customary is 13.4 mL, which is 5.7 percent more milk per cup: 13.4 / 236.588 = 0.057. Across eight cups that is 107 mL, close to half a cup of extra liquid in the bowl.

Which one to use depends on the source in front of you. Nutrition labels and FDA serving sizes use 240 mL. American recipes and American measuring cups use 236.588 mL. A cookbook from Sydney or Toronto uses 250 mL, and a European one that writes grams has skipped the argument altogether.

Why a cup of milk weighs 244 grams

Milk is mostly water. Record 171265 puts water at 88.1 g per 100 g, with fat, protein and lactose making up the rest. That composition leaves the density just above water, and the cup weight proves it: 244 / 236.588 = 1.0313 g per mL.

Run the division the other way and the two numbers agree. 244 / 1.03 = 236.9 mL, within 0.3 mL of the customary cup, so the 244 g portion was weighed against a 236.6 mL cup and not against the 240 mL label cup.

That 3.4 mL gap holds 3.5 g of milk. It is why a label reading 1 cup (240 mL) can sit beside a database entry reading 1 cup (244 g) without either being wrong: one figure describes volume under labeling rules, the other describes a weighed portion.

Fat content hardly moves the weight. A cup of 2 percent milk is also 244 g and a cup of skim is 245 g, because the fat that leaves is replaced by water. Energy is the number that changes: 122 kcal for 2 percent and 83 kcal for skim, against 149 kcal for whole.

Half cups, thirds and quarters in decimals

Half scale is where the three standards drift apart. Half a legal cup is 120 mL and 4.06 fl oz, while half a customary cup is 118.3 mL, which is exactly 4.00 fl oz. A recipe that says half a cup and means a measuring cup is 1.7 mL short of the label figure, and no one will taste it.

Thirds never land on round numbers. A third of a legal cup is 80 mL and 2.71 fl oz, and a third of a customary cup is 78.9 mL. The FDA rounding rules allow 1/3 cup increments on a label for exactly that reason.

For weights, work from the cup weight instead of the volume. Half a cup of whole milk is 122 g and 74 kcal, and a third of a cup is 81.3 g, since 244 / 3 = 81.3. A quarter cup is 61 g and 37 kcal.

Keep the fractions straight when a recipe halves twice. Half of a half cup is 60 mL, which is also 4 tablespoons, and the spoon count is often easier to hit than the fraction.

A liquid cup has a spout and a fill line for a reason. Set the cup on the counter, pour to the line, then bend down until your eye sits level with the rim; read the bottom of the curve, not the edge that climbs the sides. A dry cup held at chest height invites an extra splash, and an uneven top throws the pour off before the recipe even starts.

One cup in coffee, lattes and cereal

An 8 fl oz latte built on a double shot holds about one customary cup of steamed milk, 236.6 mL, with 60 mL of espresso underneath. Order the 12 fl oz size and the milk portion climbs to roughly 295 mL, which is 1.25 cups, and the calorie count climbs with it.

Cereal is a half cup job in most bowls: 120 mL of milk, 122 g, 74 kcal. Tea takes 30 mL, a splash by any measure, and coffee taken black takes none.

Oatmeal cooked in milk instead of water uses one cup of milk and half a cup of rolled oats, which is 40.5 g of oats at 81 g per cup. The pot starts with 244 g of milk and 40.5 g of oats, and the oats absorb most of the milk as they simmer.

Baking is where the cup habit needs care. A cup of milk at 240 mL weighs 244 g, while a cup of all purpose flour weighs 125 g, half as much for the same volume. A recipe that mixes cups of both is a volume recipe, and the scale only helps once the weights are written down.

A 10 fl oz mug works out to 1.25 cups, which the calculator reads as 300 mL, 305 g and 186 kcal for whole milk. Cafe pours sit inside that same range all day: 8 fl oz for a cappuccino, 10 for a mug of drip coffee with a jug on the side, and 12 for the large latte that started this section.

Cost per cup and keeping the carton cold

At $3.49 a gallon, one 240 mL cup costs $0.22, because 240 mL is 0.0634 of the 3,785.412 mL gallon and 3.49 x 0.0634 = 0.22. A gallon holds 15.77 legal cups (3785.412 / 240 = 15.77) or 16 customary cups, which is where the old milkman arithmetic came from.

The metric cup costs a cent more at the same price per gallon, $0.23, because it pours 10 mL more. That gap adds up to about $0.15 across a gallon, which is small enough to ignore and large enough to explain why a recipe from abroad comes out looser.

Storage matters more than the price of a cup. The FDA storage guidance puts the refrigerator at or below 40 °F (4 °C) and the freezer at 0 °F (-18 °C), and it lists milk among the foods that should not sit above 40 °F for more than two hours.

One cup also carries 276 mg of calcium, which is 21.2 percent of the 1,300 mg Daily Value used on current labels. Two cups a day covers 42 percent of it, and the rest has to come from somewhere else.

Lactose free, oat and almond milk at one cup

Lactose intolerance changes what you can drink, not how a cup is measured. One cup is still 240 mL on a label and 236.6 mL in a measuring cup. What changes is the weight of the liquid and the calories behind it. Lactose free whole milk is ordinary whole milk with lactase added, the enzyme that splits lactose into glucose and galactose. Nothing is removed, so the 244 g cup, the 149 kcal and the 7.69 g of protein stay where they are, and only the sugar line on the panel moves.

Plant milks are mostly water, and the water is what pulls the cup weight down. Unsweetened oat milk in USDA FoodData Central record 2257046 is 90.6 g water and 48.33 kcal per 100 g, so a 240 mL cup, counted as 240 g at the density that water content implies, carries 116 kcal and 1.91 g of protein: 48.33 x 2.4 = 116 and 0.797 x 2.4 = 1.91. Unsweetened almond milk in record 2257045 is 96.5 g water and 19.3 kcal per 100 g, which makes the same cup 46 kcal and 1.57 g of protein. Against the dairy cup at 149 kcal and 7.69 g, the almond carton carries about a third of the calories and a fifth of the protein.

Calcium is where a fortified carton closes the gap. Record 2257046 lists 148.5 mg of calcium per 100 g, which comes to 356 mg in the 240 g cup (148.5 x 2.4 = 356), and record 2257045 lists 158 mg per 100 g, or 379 mg in the cup. Both sit above the 276 mg in a dairy cup, which is 244 g at 113 mg per 100 g. Those numbers hold for a fortified drink. An unfortified almond milk carries a small fraction of that calcium, so read the panel rather than the front of the carton, and shake the carton first because the added calcium settles.

The cup standard still sets the millilitres, whatever sits in the carton: 240 mL for a label cup, 236.6 mL for a measuring cup, 250 mL for a metric cup. Weight is the number that shifts. Whole milk at 1.03 g per mL puts 240 g in 232.7 mL (240 / 1.0313 = 232.7), so a scale and a cup disagree by 7 mL. Oat milk near 1.0 g per mL puts the same 240 g at the fill line. A recipe that lists grams is asking for a scale, and a recipe that lists cups is asking for a measuring cup.

The table puts four cups side by side and the calorie chart at the top of the page ranks them. Volume is identical in every row, which is the point: swapping milks changes what 240 mL weighs, not how much you pour.

For coffee and cereal, a swap by volume works and the texture is what differs. Oat milk foams and browns, almond milk stays thin, and dairy milk curdles when it meets acid. In baking, protein and fat carry structure, so a cup of almond milk sets a custard looser than a cup of whole milk, while the starch in oat milk thickens a sauce without help.