A simple plastic measuring cup for liquids

The cup is a unit of measurement for volume, used in cooking to measure bulk foods, such as granulated sugar (dry measurement), and liquids (fluid measurement). It is in common use in many countries^{citation needed}, especially those that were part of the British Empire, including the United States and most members of the Commonwealth of Nations, and nations that were influenced by them, such as Japan. This cup is not commonly used in the United Kingdom or the rest of Europe, however an informal cup referring to the volume of an average coffee cup (and thus noticeably different than the U.S. cup) is frequently used in recipes in other countries such as Germany.

Definitions

Look up cup in Wiktionary, the free dictionary.

There is no internationally agreed standard definition of the cup, which ranges in volume between 200 and 250 millilitres.^[1] Because the cup sizes generally used in the many Commonwealth countries and the United States differ only by about 13 ml (0.5 fl oz), the respective measures are close enough for cooking.

Commonwealth of Nations

Imperial cup

The imperial cup was defined as half an imperial pint. The unit is no longer in use.

1 imperial cup	=	0.5	imperial pints
	=	10	imperial fluid ounces
	=	284.130625	millilitres ≈ 284 ml
	≈	19	international tablespoons[2][3]
	≈	14¼	Australian tablespoons[4]
	≈	1.2009	U.S. customary cups
	≈	9.6076	U.S. customary fluid ounces

Metric cup

In Australia, Canada, New Zealand one cup is defined as 250 millilitres. This is the commonly used cup.

1 metric cup	=	250	millilitres
	=	16⅔	international tablespoons
	=	12½	Australian tablespoons
	≈	8.7988	imperial fluid ounces
	≈	8.4535	U.S. customary fluid ounces

United States

United States customary cup

United States customary cup is defined as half a U.S. pint.

1 U.S. customary cup	=	0.5	U.S. pints
	=	8	U.S. fluid ounces
	=	236.5882365	millilitres ≈ 237 ml
	≈	15⅔	international tablespoons[5]
	≈	11¾	Australian tablespoons
	≈	0.8327	imperial cups
	≈	8.3267	imperial fluid ounces

United States "legal" cup

The cup currently used in the United States for nutrition labelling is defined in United States law^[6] as 240 ml.^[7][8]

1 U.S. "legal" cup	=	240	millilitres
	=	16	international tablespoons
	=	12	Australian tablespoons
	≈	8.1154	U.S. customary fluid ounces
	≈	8.4468	imperial fluid ounces

Japan

Japanese cup

The Japanese cup is currently defined as 200 ml.

1 Japanese cup	=	200	millilitres
	≈	7.0390	imperial fluid ounces
	≈	6.7628	U.S. customary fluid ounces

Gō

The traditional Japanese cup, the gō, is approximately 180 ml. 10 gō make one shō, the traditional flask size, approximately 1.8 litres. Gō cups are typically used for measuring rice, and sake is typically sold by both the cup (180 ml) and flask (1.8 litre) sizes.

1 gō	=	2401/13310	litres[9]
	≈	180.39	millilitres ≈ 180 ml
	≈	6.3489	imperial fluid ounces
	≈	6.0997	U.S. customary fluid ounces

Using volume measures to estimate mass

In Europe, cooking recipes normally state any liquid volumes larger than a few tablespoons in millilitres, the scale found on most measuring cups worldwide. Non-liquid ingredients are normally weighed in grams instead, using a kitchen scale, rather than measured in cups. Some recipes in Europe use the decilitre (1 dl = 100 ml) as a cup-like measure. For example, where an American customary recipe might specify "1 cup of sugar and 2 cups of milk", a European recipe might specify "200 g sugar and 500 ml of milk" (or ½ litre or 5 decilitres). Conversion between the two measures must take into account the density of the ingredients.

Notes and references

1. ^ Note also that cup sizes in recipes do not necessarily equate serving sizes for beverages. For example, a cup of brewed coffee in the U.S. is traditionally only 6 U.S. fluid ounces (180 ml).
2. ^ In the absence of measuring cups, tablespoons can be used for volume measurement.
3. ^ The term international tablespoon as used in this article refers to the 15 ml (~½ fl oz) tablespoon used in most countries.
4. ^ The Australia tablespoon is defined as 20 ml (~⅔ fl oz)
5. ^ Note: 1 U.S. customary cup = 16 tablespoons exactly using the old U.S. customary tablespoon of ½ U.S. fl oz.
6. ^ (21 CFR 101.9 (b) (5) (viii)
7. ^ U.S. Government Printing Office—Electronic Code of Federal Regulations
8. ^ U.S. Food and Drug Administration—Guidelines for Determining Metric Equivalents of Household Measures
9. ^ by 1891 definition
10. ^ One gram per millilitre is roughly equivalent to one avoirdupois ounce per fluid ounce or, more specifically:

    1 g/ml ≈ 1.002 av oz/imp fl oz

    Note that the kilogram was originally defined as the mass of one litre of water and, similarly, the imperial gallon was originally defined as the volume occupied by ten avoirdupois pounds of water. The slight discrepancy is due to the fact that water of different temperatures was used—about 4 °C (39 °F) for the kilogram definition and 62 °F (17 °C) for the imperial gallon. The U.S. fluid ounce is slightly larger.

    1 g/ml ≈ 1.043 av oz/U.S. fl oz

11. ^ 1 g/ml is a good rough guide for other water-based liquids such as milk (the density of milk is about 1.03–1.04 g/ml).
12. ^ The density of water ranges from about 0.96 to 1.00 g/ml dependent on temperature and pressure. The table above assumes a temperature range 0–30°C (32–86°F). This variation is not generally a concern when cooking.
    • Water density calculator
    • The Physics Factbook
13. ^ Since an imperial cup of water weighs approximately 10 avoirdupois ounces and five imperial cups are approximately equal to six U.S. cups, one U.S. cup of water weighs approximately 8⅓ avoirdupois ounces.
14. ^ ^{a b c} L. Fulton, E. Matthews, C. Davis: Average weight of a measured cup of various foods. Home Economics Research Report No. 41, Agricultural Research Service, United States Department of Agriculture, Washington, DC, 1977.