Cooking Conversions

Volume conversions across the US cup / tbsp / tsp / fl oz family and metric ml / l, plus the alternate 250 ml "metric cup". When you pick an ingredient (flour, sugar, butter, honey, …), the tool also weighs your amount in grams, kilograms, ounces, and pounds using a published bulk density. Densities are approximations — real ingredients vary with brand, humidity, and how packed the spoonful is.

The cup is the least standard unit in the kitchen. A US customary cup is 236.588 ml, the US legal cup used on nutrition labels is 240 ml, the metric cup common in Australia and much of Europe is 250 ml, and older British recipes may mean the imperial cup of about 284 ml. A recipe that says "1 cup" without saying which can therefore be off by a fifth. Tablespoons diverge too: 15 ml almost everywhere, but 20 ml in Australia, which is four teaspoons rather than three.

For anything that packs, the density figure is the weakest link, and flour is the worst case. Scooping a cup straight from the bag compresses the flour and can weigh 20% more than the same cup filled by spooning and levelling, which is a difference large enough to change the texture of bread. Brown sugar is worse still, since recipes usually assume it is pressed in. Honey, syrup and oil are well behaved by comparison because liquids do not compact.

That is the real argument for weighing. A gram figure means the same thing in every kitchen, which a cup does not, and the conversions here are most useful as a way to get from a volume recipe to a weight you can repeat. Where a recipe depends on exact ratios, as baking generally does, take the weight as authoritative and treat the volume as a rough guide. Note also that fluid ounces measure volume while ounces measure weight, and the two are only interchangeable for water.