Units of measurement in France before the French Revolution

Before the Revolution French units of measurement were based on the Carolingian

Carolingian Renaissance

In the history of ideas the Carolingian Renaissance stands out as a period of intellectual and cultural revival in Europe occurring from the late eighth century, in the generation of Alcuin, to the 9th century, and the generation of Heiric of Auxerre, with the peak of the activities coordinated...

system, introduced by the first Holy Roman Emperor

Holy Roman Emperor

The Holy Roman Emperor is a term used by historians to denote a medieval ruler who, as German King, had also received the title of "Emperor of the Romans" from the Pope...

Charlemagne

Charlemagne was King of the Franks from 768 and Emperor of the Romans from 800 to his death in 814. He expanded the Frankish kingdom into an empire that incorporated much of Western and Central Europe. During his reign, he conquered Italy and was crowned by Pope Leo III on 25 December 800...

which in turn were based on ancient Roman measures. Charlemagne brought a consistent system on measures across the entire empire. However, after his death the empire fragmented and many rulers introduced their own variants of the units of measure.

Some of Charlemagne’s units of measure, such as the pied du roi (the king’s foot) remained virtually unchanged for about a thousand years, while others, such as the aune (ell

Ell

An ell , is a unit of measurement, approximating the length of a man's arm.Several national forms existed, with different lengths, includingthe Scottish ell ,the Flemish ell ,the French ell...

- used to measure cloth) and the livre

Livré

Livré-la-Touche is a commune in the Mayenne department in north-western France. Prior to October 6, 2008, it was known as Livré....

(pound

Pound (mass)

The pound or pound-mass is a unit of mass used in the Imperial, United States customary and other systems of measurement...

) varied dramatically from locality to locality. By the time of the revolution, the number of units of measure had grown to the extent that it was almost impossible to keep track to them.

History

Although the pre-revolutionary era (before 1795) when France used a system of measures that had many of the characteristics of the modern Imperial System of units, there was no unified system of measurement in France. Whereas in England the Magna Carta

Magna Carta

Magna Carta is an English charter, originally issued in the year 1215 and reissued later in the 13th century in modified versions, which included the most direct challenges to the monarch's authority to date. The charter first passed into law in 1225...

decreed that "there shall be one unit of measure throughout the realm", Charlemagne and successive kings had tried but failed to impose a unified system of measurement in France.

The names and relationships of many units of measure were adopted from Roman units of measure and many more were added – it has been estimated that there were seven or eight hundred different names for the various units of measure. Moreover the quantity associated with each unit of measure differed from town to town and even from trade to trade to the extent that the lieue (league) could vary from 3.268 km in Beauce

Beauce

Beauce is a natural region in northern France, located between the Seine and Loire rivers. It now comprises the Eure-et-Loir département and parts of Loiret, Essonne and Loir-et-Cher. The region shared the history of the province of Orléanais and the county of Chartres, which is its only major...

to 5.849 km in Provence

Provence

Provence ; Provençal: Provença in classical norm or Prouvènço in Mistralian norm) is a region of south eastern France on the Mediterranean adjacent to Italy. It is part of the administrative région of Provence-Alpes-Côte d'Azur...

. It has been estimated that on the eve of the Revolution a quarter of a million different units of measure were in use in France. Although certain standards, such as the pied du roi (the King's foot) had a degree of pre-eminence and were used by savant

Savant syndrome

Savant syndrome , sometimes referred to as savantism, is a rare condition in which people with developmental disorders have one or more areas of expertise, ability, or brilliance that are in contrast with the individual's overall limitations...

s, many traders chose to use their own measuring devices giving scope for fraud and hindering commerce and industry.

As an example, the weights and measures used at Pernes-les-Fontaines

Pernes-les-Fontaines

Pernes-les-Fontaines is a commune in the Vaucluse department in the Provence-Alpes-Côte d'Azur region in southeastern France.-References:*...

in south eastern France differ from those catalogued later in this article as having been used in Paris. In many cases the names are different, while the livre is shown as being 403 g, as opposed to 489 g - the value of the livre du roi.

Tables of units of measure

These definitions use the Paris definitions for the coutume of Paris, and definitions for other Ancien régime civil jurisdictions varied, at times quite significantly.

Length

The mediaeval royal units of length were based on the toise and in particular the toise de l'Écritoire, the distance between the fingertips of the outstretched arms of a man which was introduced in 790 AD by Charlemagne

Charlemagne

. The toise has 6 pied (feet) each of 326.6 mm (12.86 in). In 1668 the reference standard was found to have been deformed and it was replaced by the toise du Châtelet which, to accommodate the deformation of the earlier standard, was 11 mm (0.55 %) shorter. In 1747 this toise was replaced by a new toise of near-identical length - the Toise du Pérou, custody of which was given to l'Académie des Sciences au Louvre.

Although the pouce (inch), pied (foot) and toise were fairly consistent throughout most of pre-revolutuionary France, some areas had local variants of the toise. Other units of measure such as the aune (ell

Ell

An ell , is a unit of measurement, approximating the length of a man's arm.Several national forms existed, with different lengths, includingthe Scottish ell ,the Flemish ell ,the French ell...

), the perche (perch/rood), the arpent and the lieue (league

League (unit)

A league is a unit of length . It was long common in Europe and Latin America, but it is no longer an official unit in any nation. The league originally referred to the distance a person or a horse could walk in an hour...

) had a number of variations, particularly the aune (which was used to measure cloth

The loi du 19 frimaire an VIII (Law of 10 December 1799) states that one decimal metre is exactly 443.296 French lines, or 3 pieds 11.296 lignes de la "Toise du Pérou". Thus the French royal foot is exactly 9000/27706 metres ( about 0.3248 m).

In Quebec

Quebec

Quebec or is a province in east-central Canada. It is the only Canadian province with a predominantly French-speaking population and the only one whose sole official language is French at the provincial level....

, the surveys in French units were converted using the relationship 1 pied (of the French variety, the same word being used for English feet as well) = 12.789 English 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. This makes the Quebec pied very slightly smaller (about 4 parts in one million) than the pied used in France.

Table of length units
Unit	Relative value	SI Si Si, si, or SI may refer to :- Measurement, mathematics and science :* International System of Units , the modern international standard version of the metric system... value	Imperial value	Notes
point	1/12³	~0.188 mm	~7.401 thou	This unit is usually called the Truchet point in English.
ligne	1/12²	~2.256 mm	~88.81 thou	This corresponds to the line, a traditional English unit.
pouce	1/12	~27.07 mm	~1.066 in	This corresponds to the 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... , a traditional English unit.
pied du roi	1	~32.48 cm	~1.066 ft	Commonly abbreviated to 'Pied', this corresponds to the foot, a traditional English unit.
toise Toise A toise is a unit of measure for length, area and volume originating in pre-revolutionary France. In North America, it was used in colonial French establishments in early New France, French Louisiana , and Quebec...	6	~1.949 m	~6.394 ft, or ~2.131 yd	This corresponds to the fathom Fathom A fathom is a unit of length in the imperial and the U.S. customary systems, used especially for measuring the depth of water.There are 2 yards in an imperial or U.S. fathom... , a traditional English unit. Unlike the fathom, it was used in both land and sea contexts.
Paris
perche d'arpent	22	~7.146 m	~7.815 yd
arpent Arpent An arpent is a unit of length and a unit of area. It is a pre-metric French unit based on the Roman actus. It is used in Quebec as well as in some areas of the United States that were part of French Louisiana.-Unit of length:...	220	~71.46 m	~78.15 yd
lieue ancienne	10,000	~3.248 km	~2.018 miles	This is the old French league, defined as 10,000 (a myriad) feet. It was the official league until 1674.
lieue de Paris	12,000	~3.898 km	~2.422 miles	This league was defined in 1674 as exactly 2000 toises. After 1737, it was also called the "league of bridges and roads" (des Ponts et des Chaussées).
lieue des Postes	13,200	~4.288 km	~2.664 miles	This league is 2200 toises. It was created in 1737.
lieue de 25 au degré	~13,692	~4.448 km	~2.764 miles	Linked to the circumference of the Earth, with 25 lieues making up one degree of a great circle. It was measured by Picard in 1669 to be 2282 toises.
lieue tarifaire	14,400	~4.678 km	~2.907 miles	This league is 2400 toises. It was created in 1737.
North America
perche du roi	18	~5.847 m	~6.394 yd	This perch was used in Quebec Quebec Quebec or is a province in east-central Canada. It is the only Canadian province with a predominantly French-speaking population and the only one whose sole official language is French at the provincial level.... and Louisiana Louisiana Louisiana is a state located in the southern region of the United States of America. Its capital is Baton Rouge and largest city is New Orleans. Louisiana is the only state in the U.S. with political subdivisions termed parishes, which are local governments equivalent to counties...
arpent	180	~58.47 m	~63.94 yd
Local
perche ordinaire	20	~6.497 m	~7.105 yd	This perch was used locally.
arpent	200	~64.97 m	~71.05 yd

The French typographic point
Point (typography)
In typography, a point is the smallest unit of measure, being a subdivision of the larger pica. It is commonly abbreviated as pt. The point has long been the usual unit for measuring font size and leading and other minute items on a printed page....

, the Didot
Didot
Didot is the name of a family of French printers, punch-cutters and publishers. Through its achievements and advancements in printing, publishing and typography, the family has lent its name to typographic measurements developed by François-Ambroise Didot and the Didot typeface developed by Firmin...

point, was 1/72 French inches, i.e. two royal points. The French pica, called Cicéro, measured 12 Didot points.

Area

Table of area units
Unit	Relative value	SI Si Si, si, or SI may refer to :- Measurement, mathematics and science :* International System of Units , the modern international standard version of the metric system... value	Imperial value	Notes
pied carré	1	~1055 cm²	~1.136 sq ft	This is the French square foot.
toise carrée	36	~3.799 m²	~40.889 sq ft, or ~4.543 sq yd	This is the French square fathom.
Paris
perche d'arpent carrée	484	~51.07 m²	~61.08 sq yd	This was the main square perch in old French surveying. It is a square 22 feet on each side.
vergée Vergée A vergée, or vergee, is a unit of area, a quarter of the French acre. Other spellings include vergie and vrégie. It is not an SI unit. The SI unit of area is the square metre.The term derives from Latin virga...	12,100	~1277 m²	~1527 sq yd	This is a square 5 perches on each side.
acre Acre The acre is a unit of area in a number of different systems, including the imperial and U.S. customary systems. The most commonly used acres today are the international acre and, in the United States, the survey acre. The most common use of the acre is to measure tracts of land.The acre is related... , or arpent carré Arpent An arpent is a unit of length and a unit of area. It is a pre-metric French unit based on the Roman actus. It is used in Quebec as well as in some areas of the United States that were part of French Louisiana.-Unit of length:...	48,400	~5107 m²	~6108 sq yd, or ~1.262 acres	The French acre is a square 10 perches on each side.
North America
perche du roi carrée	324	~34.19 m²	~40.89 sq yd	This square perch was used in Quebec and Louisiana. It is a square 18 feet on each side.
vergée	8,100	~854.7 m²	~1022 sq yd	This is a square 5 perches on each side.
acre, or arpent carré	32,400	~3419 m²	~4089 sq yd, or ~0.8448 acres	This acre is a square 10 perches on each side. Certain U.S. states have their own official definitions for the (square) arpent Arpent An arpent is a unit of length and a unit of area. It is a pre-metric French unit based on the Roman actus. It is used in Quebec as well as in some areas of the United States that were part of French Louisiana.-Unit of length:... , which vary slightly from this value.
Local
perche (ordinaire) carrée	400	~42.21 m²	~50.48 sq yd	This square perch was used locally. It is a square 20 feet on each side.
vergée	10,000	~1055 m²	~1262 sq yd	This is a square 5 perches on each side.
acre, or arpent carré	40,000	~4221 m²	~5048 sq yd, or ~1.043 acres	This acre is a square 10 perches on each side.

Volume - Liquid measures

Table of (liquid) volume units
Unit	Relative value	SI Si Si, si, or SI may refer to :- Measurement, mathematics and science :* International System of Units , the modern international standard version of the metric system... value	U.S. value	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... value	Notes
roquille	1/32	~29.75 ml
posson	1/8	~119 ml
demiard	1/4	~238 ml	~1/2 pint		Etymologically, 'demi' in French means 'half', in this case, half a chopine, and - conveniently - also half a (US) pint.
chopine	1/2	~476.1 ml	~1 pint	~0.84 pint
pinte	1	~952.1 ml	~2.01 pint	~1.68 pint	Although etymologically related to the English unit 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... , the French pint is about twice as large. It was the main small unit in common use, and measured 1/36 of a cubic French foot.
quade	2	~1.904 L	~1/2 gallon	~0.42 gallon
velte	8	~7.617 L	~2.01 gallon	~1.68 gallon
quartaut	72	~68.55 L			A quartaut is 9 veltes.
feuillette	144	~137.1 L
muid	288	~274.2 L			The muid is defined as eight French cubic feet.
cubic
pouce cube	1/48	~19.84 ml			This is the French cubic inch.
pied cube	36	~34.28 L			This is the French cubic foot. In ancient times, a cubic foot was also known as an amphora Amphora (measure) The amphora, or amphora quadrantal was a unit for measuring liquids or bulk goods in the Roman Empire, and for estimating the size of ships and the production of vineyards.The volume of a standard amphora is equal to one cubic foot.... when measuring liquid volume.

Volume - Dry measures

Table of (dry) volume units
Unit	Relative value	SI value	imperial value	U.S. value	Notes
litron		~793.5 mL	The 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... is etymologically related to this unit.
quart		~3.174 litre
boisseau	1	~12.7 litre	A boisseau was defined as of a French cubic foot.
minot Minot (unit) The minot is an old unit of dry volume, used in France prior to metrication. The unit was equivalent to three French bushels , half a mine, and one quarter of a setier. The size of the minot is comparable to the US and Imperial bushels.The name minot derives from the larger unit, the mine, with...	3	~38.09 litre
mine	6	~76.17 litre
setier	12	~152.3 litre
muid	144	~1828 litre
cubic
pouce cube		~19.84 cm³	~19.84 cubic centimetres (1.2 cu in)		This is the French cubic inch.
pied cube	2.7	~34.28 dm³	~34.28 cubic decimetres (2,090.2 cu in)		This is the French cubic foot.

Mass

According to the law of 19 Frimaire An VIII (December 10, 1799),

The kilogramme is equal to 18,827.15 grains. The kilogramme is, in addition, defined as the weight of 1 dm³ of distilled water at 4 degrees centigrade, i.e. at maximum density.

Traditionally, the French pound (livre) was defined as the mass of exactly of a French cubic foot of water. When the kilogramme was defined, knowledge that a pied du roi cube filled with water masses exactly 70 French pounds was apparently lost. According to the traditional (cubic foot) definition, one livre would have been about 489.675 grammes. According to the kilogramme definition, one livre was about 489.506 grammes. The difference is about 0.035%. However, a small difference in salinity (i.e. the difference between distilled water and very good quality drinking water) is enough to explain this difference.

The units in the following table are (except for the talent) calculated based on the kilogramme definition of the livre.

Table of mass units
Unit	Relative value	SI Si Si, si, or SI may refer to :- Measurement, mathematics and science :* International System of Units , the modern international standard version of the metric system... value	Imperial value	Notes
Poids de marc, mid 14th – late 18th century
prime	1/24³ once	~2.213 mg
grain	1/24² once	~53.11 mg	~0.8197 grains	This is the French grain Grain (measure) A grain is a unit of measurement of mass that is nominally based upon the mass of a single seed of a cereal. From the Bronze Age into the Renaissance the average masses of wheat and barley grains were part of the legal definition of units of mass. However, there is no evidence of any country ever... .
denier	1/24 once	~1.275 g	~19.67 grains
gros	1/8 once	~3.824 g	~2.158 dr
once	1/16	~30.59 g	~1.079 oz	This is the French ounce Ounce The ounce is a unit of mass with several definitions, the most commonly used of which are equal to approximately 28 grams. The ounce is used in a number of different systems, including various systems of mass that form part of the imperial and United States customary systems... .
marc	1/2	~244.8 g	~8.633 oz
livre	1	~489.5 g	~1.079 lb	This is the French pound Pound (mass) The pound or pound-mass is a unit of mass used in the Imperial, United States customary and other systems of measurement... .
quintal	100	~48.95 kg	~107.9 lb	This is the French hundredweight Hundredweight The hundredweight or centum weight is a unit of mass defined in terms of the pound . The definition used in Britain differs from that used in North America. The two are distinguished by the terms long hundredweight and short hundredweight:* The long hundredweight is defined as 112 lb, which... .
talent
talent	~70.02	~34.28 kg	~75.57 lb	This is the mass of one French cubic foot of water; this value is calculated based on the French cubic foot and an assumed water density of 1 g/cm³; other values in this table are based on the kilogramme definition.
bullion
felin	1/1280	~382.4 mg	~5.902 grains
maille	1/640	~764.9 mg	~11.8 grains
estelin	1/320	~1.53 g	~23.61 grains