The quart is a unit of volume

Volume

Volume is the quantity of three-dimensional space enclosed by some closed boundary, for example, the space that a substance or shape occupies or contains....

 (for either the imperial

Imperial unit

The system of imperial units or the imperial system is the system of units first defined in the British Weights and Measures Act of 1824, which was later refined and reduced. The system came into official use across the British Empire...

 or United States customary units

United States customary units

United States customary units are a system of measurements commonly used in the United States. Many U.S. units are virtually identical to their imperial counterparts, but the U.S. customary system developed from English units used in the British Empire before the system of imperial units was...

) equal to a quarter of a gallon

Gallon

The gallon is a measure of volume. Historically it has had many different definitions, but there are three definitions in current use: the imperial gallon which is used in the United Kingdom and semi-officially within Canada, the United States liquid gallon and the lesser used United States dry...

, two pint

Pint

The pint is a unit of volume or capacity that was once used across much of Europe with values varying from state to state from less than half a litre to over one litre. Within continental Europe, the pint was replaced with the metric system during the nineteenth century...

s, or four cup

Cup (unit)

The cup is a customary unit of measurement for volume, used in cooking to measure liquids and bulk foods such as granulated sugar...

s. Since gallons of various sizes have historically been in use, quarts of various sizes have also existed; see gallon

Gallon

The gallon is a measure of volume. Historically it has had many different definitions, but there are three definitions in current use: the imperial gallon which is used in the United Kingdom and semi-officially within Canada, the United States liquid gallon and the lesser used United States dry...

 for further discussion. Three of these kinds of quarts remain in current use, all approximately equal to one litre

Litre

pic|200px|right|thumb|One litre is equivalent to this cubeEach side is 10 cm1 litre water = 1 kilogram water The litre is a metric system unit of volume equal to 1 cubic decimetre , to 1,000 cubic centimetres , and to 1/1,000 cubic metre...

. Its proper abbreviation is qt.

Definitions and Equivalencies

United States liquid quart

All traditional U.S. length and volume measures have been legally standardized for commerce using the definition of 1 yard being exactly equal to 0.9144 meter

Metre

The metre , symbol m, is the base unit of length in the International System of Units . Originally intended to be one ten-millionth of the distance from the Earth's equator to the North Pole , its definition has been periodically refined to reflect growing knowledge of metrology...

. 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 litres.

{|

|-
|1 US liquid quart ||=
|align=right|1/4||US liquid gallons
|-
|||=
|align=right|2||US liquid pint

Pint

The pint is a unit of volume or capacity that was once used across much of Europe with values varying from state to state from less than half a litre to over one litre. Within continental Europe, the pint was replaced with the metric system during the nineteenth century...

s
|-
|||=
|align=right|4||US liquid cups
|-
|||=
|align=right|32||US fluid ounce

Fluid ounce

A fluid ounce is a unit of volume equal to about 28.4 mL in the imperial system or about 29.6 mL in the US system. The fluid ounce is distinct from the ounce, which measures mass...

s
|-
|||=
|align=right|57.75||cubic inch

Inch

An inch is the name of a unit of length in a number of different systems, including Imperial units, and United States customary units. There are 36 inches in a yard and 12 inches in a foot...

es
|-
|||=
|align=right|0.946352946||litres
|-
|||≈
|align=right|33.307||imperial fluid ounces
|}

United States dry quart

The US dry quart is equal to 1/32 of a US bushel

Bushel

A bushel is an imperial and U.S. customary unit of dry volume, equivalent in each of these systems to 4 pecks or 8 gallons. It is used for volumes of dry commodities , most often in agriculture...

, exactly 1.101220942715 litres.

{|

|-
|1 US dry quart ||=
|align=right|1/32||US bushels
|-
|||=
|align=right|1/4||US dry gallons
|-
|||=
|align=right|2||US dry pints
|-
|||=
|align=right|67.2||cubic inches
|-
|||=
|align=right|1.101220942715||litres
|-
|||≈
|align=right|38.758||imperial fluid ounces
|}

Imperial quart

The imperial quart, used for both liquid or dry capacity, is equal to one quarter of an imperial gallon, or exactly 1.1365225 litres.

{|

|-
|1 imperial quart ||=
|align=right|1/4||imperial gallons
|-
|||=
|align=right|2||imperial pints
|-
|||=
|align=right|40||imperial fluid ounces
|-
|||=
|align=right|1.1365225||litres
|-
|||≈
|align=right|69.355||cubic inches
|-
|||≈
|align=right|38.430||US fluid ounces
|}

Winchester quart

The Winchester quart is an archaic measure

Winchester measure

Winchester measure is a set of legal standards of volume defined in the city of Winchester, England during the tenth century and in use, with some modifications, until the present day.-National standard:...

, roughly equal to 2 Imperial quarts or 2.25 litres. The 2.5 litre 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.