Measurement
US Cups vs Metric Cups
They sound the same but aren't — a 5.7% difference that can ruin a recipe.
US Cup
236.6 mL — the American standard
Metric Cup
250 mL — used in Australia, Canada, NZ
At a glance
| US Cup | Metric Cup | |
|---|---|---|
| Volume | 236.6 mL | 250 mL |
| Tablespoons | 16 US tbsp | 16.67 metric tbsp |
| Fluid ounces | 8 fl oz | 8.45 fl oz |
| 1 cup all-purpose flour | ≈125 g | ≈132 g |
| Used in | United States, most online recipes | Australia, New Zealand, Canada |
Pick US Cup
Following a US cookbook or recipe — most online recipes, food blogs, and American cookbooks use the US cup (236.6 mL). When in doubt, assume US.
Pick Metric Cup
Following an Australian, New Zealand, or Canadian recipe — or when precision matters in baking and the recipe source is from one of these countries.
Where the difference comes from
The US customary cup is defined as exactly 8 US fluid ounces, which equals 236.588 mL — commonly rounded to 236.6 mL. It descends from the older English system of measures and has been codified in US law since the 19th century.
The metric cup is a more recent creation, adopted by Australia in 1970 during metrication and subsequently used in New Zealand and, for cooking purposes, Canada. It was set at an even 250 mL to align cleanly with the metric system's base-10 structure.
The difference between them is 13.4 mL, or about 5.7%. For a glass of water, this is irrelevant. For a recipe requiring multiple cups of flour, the accumulated difference can shift hydration ratios enough to affect texture and rise.
When the difference matters
In savory cooking, the 5.7% gap almost never matters. Adding slightly more or less stock, wine, or chopped vegetables rarely changes a dish perceptibly. The tolerance for variation is wide.
In baking, the difference can matter — especially in recipes where ratios are critical. Bread dough, croissants, and pastry rely on specific flour-to-water ratios (hydration). A dough that is 5–6% more or less hydrated than intended behaves differently: it may be stickier, harder to shape, or have a different crumb structure. For high-precision baking, always verify which cup standard the recipe uses.
Practically speaking: if a recipe on an Australian blog says "1 cup milk" and you use a US cup, you are using 94.6% of the intended amount. Most recipes can absorb that error. For everyday cooking and most baking, you will not notice. For high-precision work, weigh ingredients in grams instead — then cup size is irrelevant entirely.
How to convert between them
To convert US cups to metric cups: multiply by 0.9464. One US cup = 0.946 metric cups.
To convert metric cups to US cups: multiply by 1.057. One metric cup = 1.057 US cups.
In practice, most conversions are approximate: - 1 metric cup ≈ 1 US cup + 1 tablespoon (roughly) - 4 metric cups ≈ 4.2 US cups
The simplest solution for recipes that cross cup standards is to convert to grams using the weight of each specific ingredient. A kitchen scale eliminates the ambiguity entirely and gives you more consistent results regardless of which country's recipe you are using.