US Legal Cups to US Cups (cup (legal) to cup)

1 US legal cup equals 1.014420681 US cups (rounded).

1 US legal cup = 1.014420681 US cups

How to convert US legal cups to US cups

To convert US legal cups to US cups, multiply the number of US legal cups by 1.014420681. The factor is rounded to 10 significant digits. To go the other way, multiply US cups by 0.9857843188 (rounded).

US cups = US legal cups × 1.014420681

Example: 10 US legal cups = 10.14420681 US cups.

Pints, quarts, gallons and fluid ounces differ between the US and the UK. Units are labeled 'US' or 'imperial' to avoid confusion.

About these units

US Legal Cup (cup (legal))

US customaryCurrent unit

Exactly 240 mL, the 'cup' defined by US food-labeling law.

Nutrition labels in the United States do not use the traditional cup. Federal law, tied to FDA labelling rules, defines the legal cup as exactly 240 mL, which is a round metric figure sitting close to the customary cup of 8 US fluid ounces (about 236.6 mL, as NIST lists it). The difference is about 1.4 percent, small enough to matter little for a serving size.

The metric cup of 250 mL, used in Australia, Canada, New Zealand and some other countries, is a separate, slightly larger measure, and the legal cup is about 0.96 of it. Older cups varied far more. The Japanese go was about 180 mL and was legally defined in 1891, the Russian stakan about 246 mL and the Dutch kopje about 150 mL. An 1894 British book described a cup as about 6 imperial fluid ounces. Without a stated standard, a recipe cup can therefore differ noticeably from country to country.

1 US legal cup = 0.24 liters (exactly).

Sources: Wikipedia: Cup (unit); NIST Guide to the SI, Appendix B.8: conversion factors

US Cup (cup)

US customaryCurrent unit

One sixteenth of a US gallon, 236.588 mL (8 US fluid ounces). The standard US recipe cup.

Cups began as household drinking vessels, not scientific units, which is why they remain the messiest measures in the kitchen. The US customary cup was defined by slicing up the gallon: half a pint, or eight US fluid ounces, about 236.6 milliliters. Unlike the larger units, nobody ever fixed it to a physical vessel, so it exists only as a fraction of the gallon.

The customary cup is not the only American cup. For nutrition labels, US regulation defines a cup as exactly 240 milliliters, a rounder figure that sits slightly above the customary size. Packaged foods therefore list a serving in the legal cup while a measuring cup from the hardware store follows the customary definition. The gap is 3.4 milliliters, which hardly matters for soup but can matter in baking. Cup measures also hide the weight of dry ingredients, since a cup of sifted flour and a cup of packed flour differ substantially, which is why much of the world prefers grams.

1 US cup = 0.2365882365 liters (exactly).

Sources: Wikipedia: Cup (unit); NIST SP 811, Appendix B.8: conversion factors for volume; 21 CFR 101.9: nutrition labeling household measures

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