US legal cup to Imperial fluid ounce

The US legal cup (nutrition labels) is exactly 240 mL. The US customary cup (8 US fl oz) is approximately 236.6 mL. In cooking, both are treated as 240 mL; the difference is negligible for most recipes.

The US legal cup is 240 mL; the Australian metric cup is 250 mL — about 4% larger. Australian recipes calling for 4 cups use 1,000 mL vs 960 mL with US cups, which can matter in baking.

Approximately 4.167 US legal cups fit in one liter (1,000 mL ÷ 240 mL). Practically, 4 cups ≈ 960 mL ≈ 1 liter — often used interchangeably in cooking.

Most US drip coffee makers define a "cup" as 5 or 6 fl oz (148–177 mL) — smaller than the standard 8 fl oz measuring cup. A "12-cup" coffee maker typically makes 60–72 fl oz, or only about 7–9 standard 8-oz cups.

Baking is chemistry — flour, fat, liquid, and leavening interact in precise ratios. Too much flour (even 10–15% extra from packing a cup too tightly) produces dense, dry results. Too much liquid makes cake batter collapse. Cooking is more forgiving because sautéing, braising, and roasting rely on technique and taste adjustment, not exact chemical reactions. This is why professional bakers weigh ingredients in grams rather than using volume cups — a cup of flour can vary from 120 to 160 g depending on how it is scooped.

When the UK metricated in the 1990s, spirits measures were switched to 25 mL and 35 mL because publicans needed precise, legally enforceable pour sizes — and optic dispensers were easy to replace with metric ones. Beer, however, had enormous cultural resistance: the "pint" is deeply embedded in British pub identity, and the Campaign for Real Ale lobbied hard. Parliament granted an explicit exemption allowing draft beer and cider to be sold by the imperial pint. Milk got a similar exemption. The result is a hybrid system where your gin is metric but your beer is imperial.

There are exactly 20 imperial fluid ounces in one UK pint (568 mL). In the US system, 1 pint = 16 US fluid ounces (473 mL).

The imperial fluid ounce is rarely used for commercial transactions in the UK today, which metricated in the 1990s. UK spirits servings are now legally defined in metric (25 mL or 35 mL).

When the UK metricated bar measures, the 25 mL "metric measure" replaced older imperial measures. One imperial fl oz (28.41 mL) was not adopted because the EU standardized on 25 mL. So UK shots are not exactly one fl oz.

One imperial fluid ounce equals approximately 28.413 mL. One US fluid ounce equals approximately 29.574 mL. Both round to roughly "30 mL" in casual usage, but the precise difference matters in pharmacology.