Research Note – General -

The following material is an expansion of a message that originally appeared in the SUB-ARCH list. It may prove useful to researchers who need to convert units from the original sources to modern equivalents.

Cross-Cultural Historic Units of Measurement

Compiled by Chuck Meide, June 2005

16th Century Iberian Units of Measurement

(from Smith 1993: 53-56; Hudson 1997: xvii; Chardon 1980a, 1980b)

Spanish Linear Distance:

dedo, or finger-width 1/16 pie or 17 mm
pulgada, or thumb-width 1/12 pie or 20 mm
palmo, or palm 1/4 vara or .21 meter (Philips 1986: 228=.209 m)
pie, or foot 1/3 vara or .28 meter
codo real, or royal cubit 33 dedos or .56 meter (22 inches) (Philips 1987b:296 lists 0.565 m to the codo)
vara, or yard (literally "staff" or "prod") 3 pies or 4 palmos or .835 meter
braza, or fathom 2 varas or 6 pies or 1.68 meters
milla, or Roman or Italian mile (commonly used in 15th C nautical reckoning) 1,480 meters or .8 nautical mile (1 nautical mile = 1,852 meters) or slightly less than a Castillian mile
legua legal, or legal league (land measurement) 4.19 km or 2.59 miles
legua común, or common league (land measurement) 5.572 km or 3.46 miles

Spanish Volume:

Fanega about 1 ½ bushels

Spanish Weight:

14.69 kg or about 32 lbs

Tonnage and Liquid Measure:

In Iberian countries, ship's tonnage was traditionally measured in terms of the number of barrels (tuns) of wine a ship could carry in its hold. In Spanish Castile and Andalusia, the tonelada was used to measure tonnage.
Tonelada 8 cubic codos or 1.4 cubic meters or 49.4 cubic feet
Tonelada 2 pipas (pipes or casks) weighing 27.5 arrobas (404 kg) or
Portuguese tonel =
Basque tonel macho
1.683 cubic meters
10 Viscayan toneles 12 Sevillian toneladas

16th Century Portuguese Units of Linear Measurement:

palmo .21 meter
palmo de goa .25 meter
codo .56 meters
goa or cóvado real 3 palmos de goa or .75 meter
rumo 2 goas or 6 palmos de goa or 1.5 meters

18th Century French Units of Measurement

(from Boudriot and Berti 1993: 10.)

Eighteenth century French units are often approximately 10% larger than the equivalent English measures.

Linear Distance:

The French foot, pied, measured 32.48 cm, and was divided into 12 inches— pouces—of 2.71 cm. The inch was further divided into 12 lines— lignes—of .226 cm, and finally, the line was divided into 12 points— points—measuring .0188 cm each.

The span—toise—equaled six feet or 1.95 m.

The nautical league—lieue marine—was one twentieth of a degree or 2,850.4 toises (5,565 meters)

The mile—mille—was one third of a league (950 toises) or 1,855 meters.

The fathom—brasse —was five French feet, or 1.62 meters (as opposed to the English fathom of 6 English feet).

The ell—aune—was 1.188 meters in length (used for measuring sail canvas)

The palm—palme—was 13 lignes or 2.92 cm (used for measuring circumference of masts).


The French pound—livre—weighed 0.489 kilograms. It was divided into 16 ounces—onces—of 30.563 grams each.

One hundred French pounds made the 48.9 kg quintal—quinteau—which is roughly the equivalent of the English hundredweight.

Two thousand French pounds equaled a ton—tonneau—or 978 kilograms. When measuring the burthen of ships, there was also the cubic ton, which is about 42 cubic feet or 1.43 cubic meters.

Liquid Measure:

The English quart is the equivalent of the pinte de Paris, which measured 0.93 liters. The pinte was divided into two chopines (46.5 centiliters), and the chopine was divided into two demi-chopines (23 cls), which in turn was divided into four boujarons (5.8 cls) so that 16 boujarons 1 pinte. The pot (1.86 liters) was equal to two pintes.

The French Navy needed to use larger measures, such as the barrique, a cask (roughly equivalent to the English hogshead) which held 242 liters. There is some problem translating French to English terms, as the English in the late 18th century used different measures for wine, ale, beer, and dry goods, none of which correspond exactly to French measures. The closest (about 2.5% smaller) is the English measure used for wine; this therefore is the English equivalent used by Boudriot's translator (Boudriot 1986b: 108). The French Navy also used half-hogsheads or demi-barriques of 121 liters and third-hogsheads or tierçons of 161 liters (equivalent to 1/3 of 2 hogsheads).

The ship's water casks were usually larger than single barriques, and were available in multiples of hogsheads, between two and eight. They were rated as pièces de 2 (482 liters), pièces de 3 (726 liters), pièces de 4 (968 liters), pièces de 5 (1,210 liters), pièces de 6 (1,452 liters), pièces de 7 (1,694 liters), and pièces de 8 (1,936 liters). The larger sizes were used exclusively by slave ships, as the French Navy typically didn't utilize casks larger than pièces de 4.

18th Century British Units of Measurement

(From Lavery 1987)


The weight of a heavy object (such as a cannon or anchor) would be expressed in three units: Hundredweights, quarters, and pounds.

The hundredweight (cwt.) equaled 112 pounds or four quarters (50.848 kilograms).

The quarter (qr.) equaled 28 pounds (12.712 kilograms).

The pound (lb.) equals .454 kilograms.

The ton is the equivalent of 20 hundredweight or 2,240 lbs. (1,016.96 kilograms)

Other British Measurements:

The gallon equals 4.456 liters

The ell equals 45 inches or 1.143 meters (4.5 cm shorter than the French ell).

The cord, designating a pile of wood, is usually 8 ft by 4 ft by 4 in. (2.4 m by 1.2 m by 10 cm).

The bushel is 8 gallons or 35.648 liters of dry goods, and the chaldron is 36 bushels (1,283.328 liters).

British Cooperage Measures (18th-19th centuries):

(From O'Neill 2003: 75)
Cask name/size measure
(in the provisioner's trade):
'navy tierce' 300 lbs
'pipe of port' 115 gallons
'hogshead of brandy' 60 gallons
'hogshead of whiskey' 55 gallons
(in the brewer's trade):
'pin' 9 gallons
'hogshead' 52 gallons

Comparison of English & French measures:

1 English Foot 30.48 cm 1 English Inch 2.54 cm
1 French Pied 32.48 cm 1 French Pouce 2.71 cm
1 English Pound 454 grams 1 English Cwt. 50.848 kg
1 French Livre 489 grams 1 French Quinteau 48.9 kg
1 French Livre, late 17th century 1.069 lb=.4853 kg
(Keith et al 1997)
1 English Ounce 28.375 grams
1 French Once 30.563 grams
1 English Mile 5280 English Feet 1609.344 m
1 French marine league 3.4579 English miles 5565 m

18th Century Swedish Measurements:

(From Hoving 1995)
1 Swedish foot

Carrying Capacity (on Ship):

0.296 meter
1 Swedish heavy last 2.4 long tons or 2.48 French tonneaux

Arbitrary Ways to Measure Linear Distance:

crossbow shot: the extreme distance a bolt could travel 390 yards
distance at which one could consistently hit a man 65 to 70 yards
distance at which one could sometimes hit a man 200 yards (Hudson 1997: xvii)
musket shot approximately 300 yards (Creswell 1972: 93)


Boudriot, Jean and Hubert Berti
1993 The History of the French Frigate 1650-1850. Jean Boudriot Publications, Ashley Lodge, Rotherfield, United Kingdom.
Chardon, Roland
1980a The Elusive Spanish League: A Problem of Measurement in Sixteenth-Century New Spain. Hispanic American Historical Review 60: 294-302.
1980b The Linear League in North America. Annals of the Association of American Geographers 70: 129-153
Creswell, John
1972 British Admirals of the Eighteenth Century: Tactics in Battle. Archon, New York.
Hoving, A.J.
1995 Seagoing Ships of The Netherlands. In The Heyday of Sail: The Merchant Sailing Ship 1650-1830, edited by P. Bosscher, pp. 34-54. Conway's History of the Ship, R. Gardiner, general editor. Conway Maritime Press, London.
Hudson, Charles
1997 Knights of Spain, Warriors of the Sun: Hernando de Soto and the South's Ancient Chieftoms. University of Georgia Press, Athens.
Keith, Donald H., Worth Carlin, and John de Bry
1997 A Bronze Cannon from La Belle, 1686: its Construction, Conservation, and Display. International Journal of Nautical Archaeology 26(2): 144-158.
Lavery, Brian
1987 The Arming and Fitting of English Ships of War, 1600-1815. Naval Institute Press, Annapolis, Md.
O'Neill, Timothy P.
2003 Coopering. In Traditional Crafts of Ireland, edited by D. Shaw-Smith, pp. 75-79. Revised edition. Thames & Hudson, New York.
Smith, Roger C.
1993 Vanguard of Empire: Ships of Exploration in the Age of Columbus. Oxford University Press, New York.
{Chuck Meide}
The French foot, pied, measured 32.48 cm, and was divided into 12 inches pouces of 2.71 cm. The inch was further divided into 12 lines lignes of .226 cm, and finally, the line was divided into 12 points points measuring .0188 cm each.
{Brandon Cord Bradshaw}
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