Cup (unit)

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A simple plastic measuring cup, capable of holding the volume one metric cup with a scale for U.S. fluid ounces

The cup is an English unit of volume, most commonly associated with cooking and serving sizes. It is traditionally equal to half a liquid pint in either US customary units or the British imperial system but is now separately defined in terms of the metric system at values between 15 and 14 of a liter. Because actual drinking cups may differ greatly from the size of this unit, standard measuring cups are usually used instead.

United States[edit]

Legal cup[edit]

The cup currently used in the United States for nutrition labelling is defined in United States law as 240 ml.[1][2][3]

1 U.S. "legal" cup  = 240 millilitres
= 16 international tablespoons
= 12 Australian tablespoons
8.12 U.S. customary fluid ounces
8.45 imperial fluid ounces

Customary cup[edit]

Coffee carafe showing gradiations for measuring water (right) and brewed coffee (left) in multiples of non-standard U.S. customary cups.

In the United States, the customary cup is half of a liquid pint.

1 U.S. customary cup  = 116 U.S. customary gallon
= 14 U.S. customary quart
= 12 U.S. customary pint
= 8 U.S. customary fluid ounces
= 16 U.S. customary tablespoons
= 48 U.S. customary teaspoons
236.5882365 millilitres exactly
1523 international tablespoons
11.75 Australian tablespoons
0.833 imperial cups
8.33 imperial fluid ounces

A customary "cup" of coffee in the U.S. is usually defined as 4 fluid ounces, brewed using 5 fluid ounces of water. Coffee carafes used with drip coffee makers, such as Black and Decker models, have markings for both water and brewed coffee, since the carafe is also used for measuring water prior to brewing.[4] A 12-cup carafe, for example, has markings for 4, 6, 8, 10, and 12 cups of water or coffee, which correspond to 20, 30, 40, 50, and 60 fluid ounces of water or 16, 24, 32, 40, and 48 fluid ounces of brewed coffee, respectively, the difference being the volume lost to evaporation during brewing.

Commonwealth of Nations[edit]

Metric cup[edit]

Australia, Canada, New Zealand, and some other members of the Commonwealth of Nations—being former British colonies that have since metricated—employ a "metric cup" of 250 millilitres.[5] Although derived from the metric system, it is not an official metric unit.[6]

1 cup  = 250 millilitres
= 1623 international tablespoons (15 ml each)
= 12.5 Australian tablespoons (20 ml each)
8.80 imperial fluid ounces
8.45 U.S. customary fluid ounces

A "coffee cup" is 1.5 dl or 150 millilitres or 5.07 US customary fluid ounces[citation needed], and is occasionally used in recipes. It is also used in the US to specify coffeemaker sizes (what can be referred to as a Tasse à café). A "12-cup" US coffeemaker makes 57.6 US customary fluid ounces of coffee[citation needed], or 6.8 metric cups of coffee. In older recipes cup may mean "coffee cup".

Imperial cup[edit]

The official imperial cup was half an imperial pint or 10 imperial fluid ounces. It is no longer in common use, but appears in older recipe books.[7][8][9]

1 imperial cup  = 0.5 imperial pints
= 2 imperial gills
= 10 imperial fluid ounces
284 millilitres
19 international tablespoons[10][11]
14.25 Australian tablespoons[12]
1.20 U.S. customary cups
9.61 U.S. customary fluid ounces

Canadian cup[edit]

Canada now usually employs the metric cup of 250 mL but its conventional cup was somewhat smaller than both American and imperial units.[13]

1 Canadian cup = 8 imperial fluid ounce = 1/20 imperial gallon = 227.3045 millilitres

1 tablespoon = 1/2 imperial fluid ounce

1 teaspoon = 1/6 imperial fluid ounce

International[edit]

Similar units in other languages and cultures are sometimes translated "cup", usually with various values around 15 to 14 of a liter.

Latin American cup[edit]

In Latin America, the amount of a "cup" (Spanish: taza or vaso) varies from country to country, with some intending 200 mL, others 250 mL, and still others the US legal or customary amount.

Japanese cup[edit]

The traditional Japanese unit equated with a "cup" size is the , legally equated with 2401/13310 liters in 1891. It is still used for reckoning amounts of rice and sake. Separately, the Japanese standardized a "cup" defined as 200 ml.

1 Japanese cup  = 200 millilitres
7.04 imperial fluid ounces
6.76 U.S. customary fluid ounces

Dry measure[edit]

In English units, the cup derived from measures of liquid volume is also frequently used for small amounts of dry measure for fine or granulated bulk goods such as flour and sugar. In Europe, recipes normally weigh non-liquid ingredients in grams instead, using a kitchen scale, rather than employing volume units such as milliliters. 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 0.5 litre or 5 decilitres). Conversion between the two measures must take into account the density of the ingredients, and some recipes specify both weight and volume to simplify. Many European measuring cups have additional "weight scales" besides the dL or mL scale for reckoning the weight common bulk ingredients like sugar, flour, or rice by their volume.

Volume to mass conversions for some common cooking ingredients
ingredient density
g/ml[a]
metric cup imperial cup U.S. customary cup
g oz g oz g oz
water[14] 1[b] 249–250 8.8 283–284 10 236.5882 8.3[c]
granulated sugar 0.8[17] 200 7.0 230 8.0 190 6.7
wheat flour 0.5–0.6[17] 120–150 4.4–5.3 140–170 5.0–6.0 120–140 4.2–5.0
table salt 1.2[17] 300 10.6 340 12.0 280 10.0

See also[edit]

Notes[edit]

  1. ^ One gram per millilitre is very close to one avoirdupois ounce per fluid ounce: 1 g/ml ≈ 1.002 av oz/imp fl oz This is not a numerical coincidence, but comes from the original definition of the kilogram as the mass of one litre of water, and the imperial gallon as the volume occupied by ten avoirdupois pounds of water. The slight difference is due to water at 4 °C (39 °F) being used for the kilogram, and at 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.
  2. ^ 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). The variation is too small to make any difference in cooking.[15][16]
  3. ^ 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 813 avoirdupois ounces.

References[edit]

  1. ^ (21 CFR 101.9 (b) (5) (viii)
  2. ^ U.S. Government Printing Office—Electronic Code of Federal Regulations
  3. ^ U.S. Food and Drug Administration—Guidelines for Determining Metric Equivalents of Household Measures
  4. ^ "Black and Decker Replacement Carafe". Retrieved 2016-12-30. 
  5. ^ "Standard Australian Cooking Measurements". Retrieved 2014-09-24. 
  6. ^ "coherent units". BIPM. Retrieved 2014-05-26. 
  7. ^ Rosemary Hume and Muriel Downes, Penguin Cordon Bleu Cooking, Penguin Books, 1970
  8. ^ Stephanie Alexander, The cook's companion, Penguin Books, 2004
  9. ^ Jacqueline Gérard, « La cuisine », Larousse 1980
  10. ^ In the absence of measuring cups, tablespoons can be used for volume measurement.
  11. ^ The term international tablespoon as used in this article refers to the 15 ml (~0.5 fl oz) tablespoon used in most countries.
  12. ^ The Australia tablespoon is defined as 20 ml (~23 fl oz)
  13. ^ "How Many Tablespoons in a Cup - Easy Conversions". First Health Mag. 2016-04-28. Retrieved 2016-05-08. 
  14. ^ 1 g/ml is a good rough guide for water-based liquids such as milk (the density of milk is about 1.03–1.04 g/ml).
  15. ^ Water density calculator
  16. ^ The Physics Factbook
  17. ^ 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.