Historians and researchers have tried to estimate the time it took to build the Great Pyramid of King Khufu.
The probable time was 20 years for the construction and 10 years to prepare the causeway, ramps, and foundations.
Work likely went on year round, rather than only during the summer and flood season, with between 20,000 and 30,000 workers participating in the project. The number of blocks estimated to have been used in building the Great Pyramid varies between 1,500,000 and 2,300,000. Each block weighs between 1.5 and 2.5 metric tons. However, some of the granite blocks used in the roof of the king's chamber may weigh as much as 50 tons each.
The architects and chiefs of works may have been charged also with the planning and design of the pyramid and related constructions.
The project usually was supervised by the king himself and he would visit the site from time to time.
The architect Hem-iwnu was probably the main architect of the Great Pyramid of King Khufu. Other chiefs of workers are also known, for example, the artisans Inty-Shedu and Kay, whose tombs, statues, and instruments were recently found at Giza near the workmen's village.