[91]
A construction management study conducted in 1999, in association with Mark Lehner and other Egyptologists, had estimated that the total project required an average workforce of about 13,200 people and a peak workforce of roughly 40,000.[92]

Surveys and design
Comparison of approximate profiles of the Great Pyramid of Giza with some notable pyramidal or near-pyramidal buildings. Dotted lines indicate original heights, where data is available. In its SVG file, hover over a pyramid to highlight and click for its article.
The first precise measurements of the pyramid were made by Egyptologist Flinders Petrie in 1880–1882, published as The Pyramids and Temples of Gizeh.[93] Many of the casing-stones and inner chamber blocks of the Great Pyramid fit together with high precision, with joints, on average, only 0.5 millimetres (0.020 in) wide.[94] On the contrary, core blocks were only roughly shaped, with rubble inserted between larger gaps. Mortar was used to bind the outer layers together and fill gaps and joints.[6]
The block height and weight tends to get progressively smaller towards the top. 