Cooking Unit Converter

A cup of flour is not a cup of sugar

Volume and weight are only interchangeable if you know the density of what you are measuring. A US cup of water is 236 grams, of granulated sugar about 200, of plain flour about 120, and of packed brown sugar about 220. Any converter offering a single cups-to-grams number without asking what you are measuring is giving you one ingredient's answer for all of them.

Flour is the worst offender

Scooping flour with the cup compacts it, and the same cup can hold 120 to 150 grams depending on technique. That is a 25 percent swing, which is enough to turn a cake dense or a dough unworkable. This is the main reason serious baking recipes give weights: it removes the variable entirely. Where a recipe gives cups, spoon the flour into the cup and level it rather than scooping.

Cups differ between countries

A US cup is 240 ml, a metric cup 250 ml, and an Imperial cup 284 ml. A US recipe followed with a metric cup delivers about 4 percent more of everything, which is tolerable in a stew and noticeable in a cake. Australian tablespoons are 20 ml against 15 ml almost everywhere else, so four Australian tablespoons is five of anyone else's.

Fluid ounces are two different units

A US fluid ounce is 29.57 ml; an Imperial fluid ounce is 28.41 ml. Worse, a US pint is 16 fl oz and an Imperial pint is 20, so an Imperial pint is nearly 20 percent larger. Recipes rarely state which they mean, and the origin of the recipe is usually the only clue.

Oven temperatures and gas marks

Converting oven temperatures is straightforward arithmetic, but gas marks are a separate scale: gas mark 4 is 180 Celsius or 350 Fahrenheit, and each mark is roughly 14 Celsius. Fan ovens run hotter than the dial suggests, so most guidance is to reduce a conventional recipe temperature by about 20 Celsius when using fan.