The main difference between Litre and Pint is that the Litre is a non-SI unit of volume and Pint is a imperial and customary unit of measurement
The litre (SI spelling) or liter (American spelling) (symbols L or l, sometimes abbreviated ltr) is an SI accepted metric system unit of volume equal to 1 cubic decimetre (dm3), 1,000 cubic centimetres (cm3) or 1/1,000 cubic metre. A cubic decimetre (or litre) occupies a volume of 10 cm×10 cm×10 cm (see figure) and is thus equal to one-thousandth of a cubic metre.
The original French metric system used the litre as a base unit. The word litre is derived from an older French unit, the litron, whose name came from Greek — where it was a unit of weight, not volume — via Latin, and which equalled approximately 0.831 litres. The litre was also used in several subsequent versions of the metric system and is accepted for use with the SI, although not an SI unit — the SI unit of volume is the cubic metre (m3). The spelling used by the International Bureau of Weights and Measures is “litre”, a spelling which is shared by almost all English-speaking countries. The spelling “liter” is predominantly used in American English.
One litre of liquid water has a mass of almost exactly one kilogram, because the kilogram was originally defined in 1795 as the mass of one cubic decimetre of water at the temperature of melting ice. Subsequent redefinitions of the metre and kilogram mean that this relationship is no longer exact.
The pint (symbol pt, sometimes abbreviated as “p”) is a unit of volume or capacity in both the imperial and United States customary measurement systems. In both of those systems it is traditionally one-eighth of a gallon. The British imperial pint is about 20% larger than the American pint because the two systems are defined differently. Almost all other countries have standardized on the metric system, so the size of what may be called a pint varies depending on local custom.
The imperial pint (≈ 568 ml) is used in the United Kingdom and Ireland and to a limited extent in Commonwealth nations. In the United States, two pints are used: a liquid pint (≈ 473 ml) and a less-common dry pint (≈ 551 ml). Each of these pints is one-eighth of its respective gallon, but the gallons differ. This difference dates back to 1824, when the British Weights and Measures Act standardised various liquid measures throughout the British Empire, while the United States continued to use the earlier English measure. The imperial pint consists of 20 imperial fluid ounces and the US liquid pint is 16 US fluid ounces, making the imperial fluid ounce about 4% smaller than the US fluid ounce.
All of the other former British colonies, such as Canada, Australia, South Africa and New Zealand, converted to the metric system in the 1960s and 1970s; so, while the term “pint” may still be in common use in these countries, it may no longer refer to the British imperial pint once used throughout the British Empire. In the United Kingdom, the imperial pint is the primary unit for draught beer and cider, as it is for milk sold in returnable bottles and some cartons. In the UK, legislation mandates that draught beer and cider may be sold by the imperial pint in perpetuity, and in public houses can only be sold in a third of a pint, two-thirds of a pint or multiples of half a pint, which must be served in stamped measured glasses or from government-stamped meters.Since the majority of countries in the world no longer use American or British imperial units, and most are non-English speaking, a “pint of beer” served in a tavern outside the United Kingdom and the United States may be measured by other standards. In Commonwealth countries it may be a British imperial pint of 568 ml, in countries serving large numbers of American tourists it might be a US liquid pint of 473 ml, in many metric counties it is a half-litre of 500 ml, or in some places it is another measure reflecting national and local laws and customs.Historically, units called a pint (or the equivalent in the local language) were used across much of Europe, with values varying between countries from less than half a litre to over one litre. Within continental Europe, these pints were replaced with liquid measures based on the metric system during the 19th century. The term is still in limited use in parts of France, where “une pinte” means an imperial quart, which is 2 imperial pints, whereas a pint is “une chopine”—and Central Europe, notably some areas of Germany and Switzerland, where “ein Schoppen” is colloquially used for roughly half a litre. In Spanish holiday resorts frequented by British tourists, ‘pint’ is often taken to mean a beer glass (especially a dimple mug). Half-pint and pint mugs may therefore be referred to as pinta pequeña (‘small pint’) and pinta grande (‘large pint’).
The metric unit of fluid measure, equal to one cubic decimetre. Symbols: l, L, ℓ
“You should be able to fill four cups with one litre of water.”
A measure of volume equivalent to a litre.
A unit of volume, equivalent to:
⅛ of a gallon
approximately 568 millilitres (an imperial pint)
16 US fluid ounces [473 millilitres] for liquids (a US liquid pint) or
18.62 fluid ounces [551 millilitres] for dry goods (a US dry pint).
A pint of milk.
“Please leave three pints tomorrow, milkman.”
A glass of beer, served by the pint.
a unit of liquid or dry capacity equal to one eighth of a gallon, in Britain equal to 0.568 litre and in the US equal to 0.473 litre (for liquid measure) or 0.551 litre (for dry measure).
a pint of beer
“we’ll probably go for a pint on the way home”
a pint of milk
“two pints today, please”
a measure of shellfish, the amount containable in a pint mug.