Foot (unit)


July 6, 2022

The foot (symbol ', or ft, from the English foot: "foot", or pi in Canada) is a unit of length corresponding to the length of a human foot, that is to say a little more than thirty centimeters. This unit is still used in many English-speaking countries and former colonies of the British Empire. A foot is one-third of an English yard (yard), and it is divided into twelve inches. Since the international agreement of 1959 the foot is worth exactly 0.3048 meters. Along with the cubit and the finger, the foot is the oldest unit of measurement in the history of mankind [ref. desired]. As a unit on graduated rules, it is attested from the beginning of the 3rd millennium BC. AD, where it is already divided into sixteen fingers [ref. necessary]. This so-called “digital” subdivision was the rule during Antiquity.


At the end of antiquity and especially during the Middle Ages, uncial division was preferred. This division of the foot into 12 equal parts gave rise to the thumb. It is still in effect in the imperial system of measurement units. In practically all countries, the foot—or one of its multiples, such as the yard or the fathom—was the standard unit for measuring length. From the foot of Nippur to the Egyptian foot and the Roman foot, etc., all the feet of Antiquity are deduced from each other.[ref. necessary] The feet of the Middle Ages are either preserved feet of Antiquity, or new deductions.

The Roman Foot

Towards the end of prehistory  - therefore around 5,000 years ago -  the Egyptians subdivided the Mesopotamian Nippur cubit of around 518.5 mm into only 28 fingers, instead of 30 fingers as the Sumerians did.[ref. necessary] Egyptian surveyors wanted to take advantage of a trigonometric approximation. By this very fact, they defined the measurement of the finger, which was later called "Roman finger". Sixteen of these fingers are the length of the Roman foot, more precisely said pes monetalis, or about 296⅓  millimeters. This Roman foot is also attested by graduated rulers of the time. Several of them measure approximately 296.3 mm, of which the two best-known examples are a bronze foot found in Pompeii and another, also in bronze, which is now in the Louvre. Both measure 296.3 mm. The Column of Marcus Aurelius is one hundred feet high. It has been determined to measure exactly 29.617 m. The pound is a weight deducted from the leave, the unit of volume related to the foot. Studies on the Roman pound confirm a value greater than 296 mm. Nevertheless, in the different provinces and also in Rome itself, at different times other measures were used. Rightly, they can be called: "Roman feet" too. Mention may be made in particular of the measurements of approximately 294.0 mm, 294.7 mm, 295.6 mm, 297.7 mm. The Roman foot was also preserved, as a legal and official measure, in several European countries. In the city of Augsburg, one of the oldest in Germany, founded by the Romans, the foot measured until its abolition at the end of the 19th century: 296.168 mm and in Prague - a city which, in the 14th century, was even the capital of the Holy Roman Empire - the foot, abolished on January 1, 1876, measured 296.380 mm.

Gradual and partial abandonment of the foot

During the Terror, the Montagnard Convention voted for the abolition of the foot in France by the law of August 1, 1793. This was confirmed by the law of 18 germinal year 3 (April 7, 1795) of the Thermidorian Convention and made final by the law of 19 Frimaire year 8 (December 10, 1799) under the Consulate which provides that the meter is equal to 3 feet 11 lines 296 thousandths, or 443.296 lines, with the value of the foot 144 lines 0.324 8 m. The Restoration did not attempt to restore the pi