Pieds Du Roi to Meters (pied to m)

1 pied du roi equals 0.324839385 meters (rounded).

1 pied du roi = 0.324839385 meters

How to convert pieds du roi to meters

To convert pieds du roi to meters, multiply the number of pieds du roi by 0.324839385. The factor is rounded to 10 significant digits. To go the other way, multiply meters by 3.078444444 (rounded).

meters = pieds du roi × 0.324839385

Example: 10 pieds du roi = 3.24839385 meters.

About these units

Pied Du Roi (pied)

French (Ancien Régime)Historical unit (no longer in standard use)

The 'king's foot' of the French Ancien Régime, about 32.48 cm; 12 pouces. About 6.6% longer than the English foot.

King's foot is the literal meaning of the name, and the unit was reputed to descend, with little change, from the measures of Charlemagne, which in turn drew on Byzantine and Roman practice. For about a thousand years it stayed close to the same length, though the surviving standards disagree slightly: the foot of the old toise de l'Écritoire is given as 326.6 millimetres, against about 324.8 for the later royal foot.

The figure now used for the pied du roi is 4500/13853 metre, about 32.48 centimetres or 1.066 English feet. This ratio comes from the 1799 law that defined the metre in terms of the Toise of Peru. It was divided into 12 pouces and 144 lignes, while six pieds made one toise.

Wikipedia notes that its own sources vary on details of the standards. The iron toise at the Grand Châtelet was bent before 1668 and replaced by a bar roughly 0.5 percent shorter, which shows how much a nominally fixed unit could drift. Quebec's pied, still seen in land records, is about four parts per million smaller than the French original.

1 pied du roi = 0.324839385 meters (approximately).

Sources: Wikipedia: Pied du roi; Wikipedia: Toise; Wikipedia: Traditional French units of measurement

Meter (m)

Metric (SI)Current unit

The SI base unit of length. Since 1983 it is defined as the distance light travels in a vacuum in 1/299,792,458 of a second.

Meter comes from the Greek metron, a measure. In 1791 the French National Assembly defined it as one ten-millionth of the distance from the equator to the North Pole along a great circle through Paris, after rejecting the length of a seconds pendulum because that length changes with local gravity. The surveyors Delambre and Méchain measured the meridian arc, and in 1799 a platinum bar known as the Mètre des Archives became the physical standard. NIST notes that this Earth-based meter turned out to be about 0.2 mm shorter than the true pole-to-equator fraction it was meant to represent.

The 1875 Treaty of the Meter created the CGPM and the BIPM to look after common standards, and in 1889 a platinum-iridium prototype bar took over; the original is still kept at the BIPM. In 1960 the meter was tied to 1,650,763.73 wavelengths of an orange-red krypton-86 line, and in 1983 to the speed of light, which made length a quantity derived from the time standard. The 2018 revision reworded that definition without changing the meter's size. NIST offers a handy yardstick for scale: a pace, meaning two steps, is roughly a meter or a yard.

The meter is the reference unit for length on this site.

Sources: BIPM: history of the metre; NIST: the meter and the SI redefinition; Wikipedia: Metre

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