See the charts showing how many this in a that.
Units of liquid and dry capacity mainly used in cooking and to give medicines at home.
In the United States, a teaspoon is 1/3 of a tablespoon and is equal to 4.928 922 milliliters. A study several decades ago by the U.S. Bureau of Standards found that the typical silver teaspoon and measuring teaspoon held 1½ fluid drams (about 5.5 mL), not the 1 fluid dram (about 3.7 mL) often given in reference works.
In a publication of 1975 that anticipated conversion to the metric system, the National Bureau of Standards said:
There will be no need for much change in our recipes if the new metric recipes remain volumetric and if, as anticipated, the utensils retain approximately the same ratio as the customary cup (237 ml), teaspoon (4.9 ml), and tablespoon (14.7 ml). This is easily achieved by adopting a “metric cup” of 250 ml (¼ of a liter); a “metric teaspoon” of 5 ml, and a “metric tablespoon” of 15 ml.¹
In fact, by the 1990s almost all the teaspoon measures in stores were made to contain 5 mL, and tablespoons 15 mL, and many were so marked. This is a difference that makes no difference, because few cooks measure ingredients with an accuracy of 0.1 mL.
1. National Bureau of Standards Special Publication 430.
Washington, DC: USGPO, 1975.
In Great Britain, a teaspoon is ¼ of a tablespoon, but a spoonful of a dry ingredient traditionally means a rounded spoonful, with as much heaped above the spoon edge as lies within it. (A rounded spoonful is not a heaping spoonful, which would be as much as the spoon could hold.) On this theory, a British teaspoonful of a dry ingredient would be about 7 milliliters, or a bit short of 1½ U.S. teaspoons.
An English pharmacopeia of 1618 defined the tablespoon as the volume of distilled water weighing 3 drachms, which would be about 12 milliliters. Pharmacists, and following them such respected sources as The Economist, say the British tablespoon = half of an imperial fluid ounce, or about 14.21 milliliters, so that there would be 10 tablespoons in an imperial gill and 20 in a half pint, and the teaspoon would be about 3.55 milliliters.
Cooks, however, don't seem to agree. Mrs. Beeton, author of the classic 19th-century English cookbook, says under the heading “Liquid Measure” that a quarter pint contains “6 large tablespoonfuls.” Since an imperial quarter pint (a gill) contains 5 imperial fluid ounces, that would make the “large tablespoonful” 5/6 of an imperial fluid ounce, about 23.7 milliliters, and the teaspoon about 6 milliliters.
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Last revised: 2 August 2004.