How Many Milliliters Are in a Cup of Water?

How many ml are in 1 US cup of water?

1 US cup of water equals 236.6 milliliters, usually rounded to 240 ml for kitchen use. The math comes from the US definition of the cup as 8 US fluid ounces, with each US fluid ounce being 29.5735 ml (8 times 29.57 equals 236.6 ml). For most cooking, treating a US cup as 240 ml gives accuracy within 1.5 percent, which is well within tolerance for any recipe. The US 'legal' cup used on nutrition labels by federal regulation is exactly 240 ml, which is why food packaging serving sizes use clean ml numbers. For water specifically, the ml measurement is uniquely useful because water weighs exactly 1 g per ml, so a cup of water (240 ml) weighs about 240 g. This near-equivalence doesn't apply to other liquids.

How does the metric cup compare?

The metric cup is exactly 250 milliliters, used in Australia, New Zealand, and parts of Canada. The 13.4 ml difference from the US cup (236.6 ml) is about 6 percent, enough to noticeably affect baking recipes that depend on precise ratios. For water in cooking, the gap is tolerable; 250 ml of water versus 236.6 ml doesn't change soup or pasta cooking results meaningfully. For baking, bread, and pastry where hydration percentages determine texture, the difference matters. UK imperial cups (284 ml) give about 1/4 liter per cup, also useful for rough conversion. The metric cup at 250 ml was specifically designed to make cup-to-liter math clean: 4 metric cups equal exactly 1 liter, while 4 US cups equal 946 ml (just under 1 liter).

How does this scale across larger water amounts?

For US cups of water: 1/4 cup is 60 ml (rounded), 1/2 cup is 120 ml, 3/4 cup is 180 ml, 1 cup is 240 ml, 2 cups (1 pint) is 480 ml, 4 cups (1 quart) is 946 ml (just under 1 L), 8 cups (1/2 gallon) is 1.89 L, and 16 cups (1 gallon) is 3.785 L. Going down: 1 tablespoon of water is 15 ml, and 1 teaspoon is 5 ml. These figures matter for bread and pizza dough, where hydration percentages (water weight divided by flour weight) determine texture. A 70 percent hydration dough using 500 g of flour requires 350 g (350 ml) of water; converting that to cup measurements would be 1.46 cups, which is awkward to measure accurately without weighing.

When does the ml-per-cup-of-water conversion matter most?

Bread and pizza dough are the biggest case. Hydration percentages depend on accurate water-to-flour ratios, which work cleanly in ml and grams but not in cups. A 65 percent hydration dough requires precise measurement that cup-based US recipes can't deliver. International recipes use ml universally; converting from US cups speeds up cooking. Sports and fitness hydration recommendations use ml in metric countries, with the standard adult daily intake at 2000-3000 ml depending on activity level. Cocktail and drink batching benefits from ml precision; bartenders working in metric measurements can scale recipes more cleanly than working in cups.