The everyday numbers
A US cup is exactly 8 US fluid ounces, or 16 tablespoons. In millilitres that’s 236.588 mL. For home cooking, NIST rounds the common measures like this:
| Measure | Millilitres (rounded) |
|---|---|
| 1 teaspoon | 5 |
| 1 tablespoon | 15 |
| 1 fluid ounce | 30 |
| 1 cup | 240 |
US nutrition labels also count a cup as 240 mL. The 1.4% difference from 236.6 mL doesn’t matter in a home kitchen.
Not every cup is the same
Canada’s food labelling rules and Australian recipes use a 250 mL metric cup, and Japanese recipes use a 200 mL cup. See US, UK and metric cups for the full comparison, and tablespoon and teaspoon for spoons.
For baking, weighing flour and other dry ingredients is more reliable than any cup.