The quart (abbreviation qt.) is an English unit of volume equal to a quarter gallon. It is divided into two pints or four cups. Historically, the exact size of the quart has varied with the different values of gallons over time and in reference to different commodities. Presently, three kinds of quarts remain in use: the liquid quart and dry quart of the US customary system and the imperial quart of the British imperial system. All are roughly equal to one metric liter.
The term comes from the Latin quartus (meaning one-quarter) via the French quart. However, although the French word quart has the same root, it frequently means something entirely different. In Canadian French in particular, the quart is called pinte whilst the pint is called chopine.
Since gallons of various sizes have historically been in use, the corresponding quarts have also existed with various sizes.
In the United States, all traditional length and volume measures have been legally standardized for commerce by the international yard and pound agreement of 1959 using the definition of 1 yard being exactly equal to 0.9144 meter. From this definition is derived the metric equivalencies for inches, feet, and miles; as well as area measures; and measures of volume. The US liquid quart equals 57.75 cubic inches, which is exactly equal to 0.946352946 liters.^{[1]}^{[2]}
1 US liquid quart | = | 1/4 | US liquid gallons |
= | 2 | US liquid pints | |
= | 4 | US liquid cups | |
= | 8 | US liquid gills | |
= | 32 | US fluid ounces | |
= | 57.75 | cubic inches^{[3]} | |
≡ | 0.946352946 | liters^{[2]}^{[4]} | |
≈ | 33.307 | imperial fluid ounces |
In the United States, the dry quart is equal to 1/4 of a US dry gallon, exactly 1.101220942715 liters.
1 US dry quart | = | 1/32 | US bushels |
= | 1/8 | US pecks | |
= | 1/4 | US dry gallons | |
= | 2 | US dry pints | |
= | 67.2 | cubic inches | |
≡ | 1.101220942715 | liters^{[2]}^{[4]} | |
≈ | 38.758 | imperial fluid ounces |
The imperial quart, used for both liquid or dry capacity, is equal to one quarter of an imperial gallon, or exactly 1.1365225 liters.
1 imperial quart | = | 1/4 | imperial gallons |
= | 2 | imperial pints | |
= | 40 | imperial fluid ounces | |
≡ | 1.1365225 | liters^{[5]}^{[6]} | |
≈ | 69.355 | cubic inches | |
≈ | 38.430 | US fluid ounces |
In French Canada, by federal law, the imperial quart is called pinte.^{[7]}^{[8]}^{[need quotation to verify]}
The Winchester quart is an archaic measure,^{[9]} roughly equal to 2 Imperial quarts or 2.25 liters. The 2.5 L bottles in which laboratory chemicals are supplied are sometimes referred to as Winchester quart bottles, although they contain slightly more than a traditional Winchester quart.
The reputed quart was a measure equal to two thirds of an Imperial quart, or one sixth of a gallon, about 0.7577 liters. It was previously recognized as a standard size of wine bottle in the United Kingdom, and is only slightly larger than the current standard wine bottle of 0.75 L.^{[10]}^{[11]}