Rules · Modules · Proportion
Lay out Egyptian buildings in royal cubits (≈ 52.4 cm) of seven palms of four fingers, so that every dimension and every slope can be stated in whole or simple fractional units.
1 royal cubit = 7 palms = 28 fingers ≈ 0.524 m
The cubit was the forearm made official. Master cubit rods of stone and wood, some marked with the subdivisions of palms and fingers, have been found in tombs and temples. The seven-palm cubit explains why sekeds come out in palms: a slope of “5½” is a proportion of 5½ to 7.
Grid lines in cubits are still visible on unfinished tomb walls and on masons’ sketches, and they governed the proportions of statues and reliefs as well as of buildings.
Specify the slope of a pyramid face by its seked: the number of palms (and fingers) by which the face runs inward for every cubit of rise. The height follows from half the base divided by the seked, times seven.
seked = 7 × (½ base ⁄ height) palms · angle = arctan(7 ⁄ seked)
The Great Pyramid of Khufu was laid out 440 royal cubits square and 280 cubits high, a seked of exactly 5½ palms and a slope of about 51°50′.
½ × 440 ÷ 280 × 7 = 5½ palms → arctan(7 ⁄ 5.5) ≈ 51.84°
Cut a shaft with sixteen shallow flutes or facets, give it a square abacus and a low round base: the “proto-Doric” column of the Middle Kingdom rock tombs at Beni Hasan.
Cut the obelisk from a single block of granite, square in section, tapering to about two-thirds of its base width, capped by a pyramidion, and about ten times as tall as it is wide; set them in pairs before the pylon.
height ≈ 9–11 × base width
Find a granary’s capacity from its measures: multiply length, breadth and height in cubits (or, for a round bin, the square of eight-ninths of the diameter by the height), and add half as much again to turn cubic cubits into the grain measure, the khar.
1 cubic cubit = 1½ khar
Cite this page Chris Paton, “Measure in cubits, palms and fingers”, The Textbook of Architecture, https://textbookofarchitecture.com/rule/royal-cubit. Text, drawings and models licensed under CC BY-NC 4.0.