The humble "cup" is not a universal measurement. Depending on where a recipe was written, 1 cup could mean three slightly different volumes — and in precise baking, these differences can matter.
The Three Cup Standards
| Country | Cup size |
|---|---|
| USA | 236.6ml (8 US fl oz) |
| Australia / New Zealand | 250ml |
| Canada | 250ml (metric cup) |
| UK | 284ml (traditional imperial) OR 250ml (modern metric) — confusing! |
The US cup is the smallest at 236.6ml. The Australian/Canadian metric cup is 250ml — about 5.6% larger. Over a recipe with multiple cups of flour, this difference compounds.
Does It Matter in Practice?
For most everyday cooking (pasta sauces, casseroles, soups), a 14ml difference per cup is unlikely to ruin a dish.
For baking, it can matter more. If an Australian recipe calls for 2 cups of flour (500ml, 250g) and you measure US cups (473ml, about 237g), you're using about 5% less flour — which is within the margin of normal variation in most recipes. It won't ruin a cake, but it could make a difference in bread dough hydration.
How to Handle the Difference
Option 1 — Use grams. The single best solution. Recipes that provide weights are unambiguous regardless of origin.
Option 2 — Check the recipe source. An Australian recipe will use 250ml cups. A US recipe uses 236.6ml cups. Adjust accordingly.
Option 3 — Don't worry for most recipes. The practical difference for home cooks is usually small enough to be within natural recipe variation.
The UK Situation
Old British recipes (pre-1970s) use an imperial cup of approximately 284ml. Modern UK recipes have largely adopted the metric system and rarely use cups at all — they use grams and millilitres. When a British recipe uses cups, it typically follows the metric (250ml) standard.