How many ounces are in a cup?

Eight fluid ounces make a cup. Full ladder: 3 teaspoons in a tablespoon, 16 tablespoons in a cup, 2 cups in a pint, 4 cups in a quart, 16 cups in a gallon.

Now the trap: fluid ounces measure volume, plain ounces measure weight, and they only match for water and water-like liquids. A cup of all-purpose flour weighs about 4.25 ounces. A cup of honey weighs about 12. Recipes that fail mysteriously often fail right here, which is why serious bakers weigh ingredients in grams and skip the whole problem.

Also worth knowing: the UK cup and Australian cup differ slightly from the US cup, so international recipes deserve a second look before you commit butter to them.

The weight-versus-volume gap is worth internalizing because it explains most baking failures. A cup of flour can vary by 20 percent or more depending on whether it was scooped straight from the bag, which compacts it, or spooned in and leveled. That variance is enough to change a cake's texture or make a bread dough unworkable, and no amount of careful measuring with cups eliminates it. A kitchen scale costs very little and removes the variable entirely, which is why nearly every professional recipe and most modern baking books now list grams first.

One more distinction that trips people up: a US fluid ounce and an imperial fluid ounce are not the same size, and the imperial pint contains 20 fluid ounces against the American 16. So a British recipe calling for a pint of milk wants noticeably more than an American cook would pour, and the gap compounds in anything scaled up. When following a recipe from outside the US, check which system it uses before assuming the units transfer.