US Cup vs Metric Cup
Not all cups are the same. The US cup (236.6 ml) and Australian metric cup (250 ml) differ by about 5.7% — enough to matter in baking.
Cup Standards Comparison
| Cup Standard | Volume (ml) | Used In | vs US Cup |
|---|---|---|---|
| US Customary | 236.6 ml | USA | Baseline |
| US Legal | 240 ml | Nutrition labels (US) | +1.4% |
| Metric | 250 ml | Australia, Canada, SA | +5.7% |
| Imperial | 284.1 ml | Old UK recipes | +20% |
| Japanese (合) | 200 ml | Japan (rice measure) | -15.5% |
Impact on Common Baking Ingredients
Using a metric cup (250ml) for a US recipe adds approximately 5.7% more of each ingredient. Here's the practical difference:
| Ingredient | US Cup (g) | Metric Cup (g) | Difference per cup |
|---|---|---|---|
| All-purpose flour | 120g | 127g | +7g |
| Bread flour | 127g | 134g | +7g |
| Cake flour | 100g | 106g | +6g |
| White sugar | 200g | 211g | +11g |
| Brown sugar (packed) | 220g | 232g | +12g |
| Butter (softened) | 227g | 240g | +13g |
| Rolled oats | 90g | 95g | +5g |
| Cocoa powder | 85g | 90g | +5g |
| Milk (liquid) | 245g | 259g | +14g |
| Water (liquid) | 237g | 250g | +13g |
Does It Really Matter?
For 1 cup of an ingredient, the difference is small. But it compounds:
- 3 cups of flour: US = 360g, Metric = 381g — a 21g difference that will produce noticeably denser baked goods
- For most savory cooking: negligible difference
- For precision baking (macarons, croissants): use a scale, always
The Real Solution
A kitchen scale eliminates the cup-standard problem entirely. Weight doesn't change by country. 120g flour is 120g flour everywhere in the world.