Volume and weight are not interchangeable
A cup measures volume, but a cup of flour weighs about 125 g while a cup of honey weighs around 336 g. Recipes written by weight are reproducible; recipes written in cups depend on how tightly you packed the ingredient.
Flour is the worst offender. Scooping straight from the bag compacts it and can yield 20% more than spooning it in lightly — enough to turn a cake dense.
Cups are not the same everywhere
A US cup is 236.6 ml, a metric cup is 250 ml, and an Imperial cup was 284 ml. This converter uses the US cup, which is what most online recipes assume.
For baking, the reliable fix is a kitchen scale. Professional recipes are written by weight for exactly this reason.
Why baking demands weight
Baking is chemistry with tight ratios. Too much flour relative to liquid produces a dry, dense crumb; too little and the structure collapses. Because a cup of flour can vary by 20% depending on how it was filled, volume measurement introduces error precisely where the recipe is least tolerant of it.
Cooking is far more forgiving — an extra spoonful of oil in a stir-fry changes little. This is why professional baking recipes are always written by weight while savoury recipes often are not.
The spoon-and-level method
If you have no scale, do not scoop flour directly from the bag: that compacts it. Spoon it loosely into the measuring cup, then level the top with a straight edge. This gets you close to the standard 125 g per cup that most recipes assume.
Brown sugar is the exception and is almost always packed firmly, which is why it weighs considerably more per cup than granulated sugar despite looking similar.
Frequently asked questions
How many tablespoons in a cup? +
Sixteen US tablespoons, or 48 teaspoons. A tablespoon is three teaspoons.
How many grams is a cup of flour? +
About 125 g for all-purpose flour, spooned and levelled. Scooped straight from the bag it can reach 150 g, which is enough to change the result.
Are US and UK tablespoons the same? +
Not quite. A US tablespoon is 14.79 ml, a UK one 15 ml, and an Australian tablespoon is 20 ml — a meaningful difference in a recipe using several.