Jelitto, Hans. (2015). Planetary Correlation of the Giza Pyramids - P4 Program Description. 10.13140/RG.2.1.5135.2164. For more than 4500 years people have been fascinated by the pyramids of Giza. Now, there are very strong hints for a correlation between the three great pyramids in Giza and the three inner planets of our solar system: Mercury, Venus, and Earth. This assumption originally was based on three equations, connecting the sizes of the pyramids and planets. Later on, the spatial arrangement of the pyramids and planets could precisely be correlated on the basis of the French planetary theory VSOP87 and by coordinate transformations in three-dimensional space. Because of planetary motion, the positions match only at one or a few points in time. The final outcome includes the fact that in the year 3088 the four inner planets, Mercury to Mars, will stand in a fourfold conjunction within a minimum angular range (ecliptic longitudes) of 3.4°, combined with a simultaneous Mercury transit in front of the solar disk. Furthermore during the last decades, scientists have been searching with high-tech methods for undetected chambers in the Cheops Pyramid. An interesting aspect of the planetary correlation is that it precisely defines a “Sun position” and a “Mars position” inside the Cheops Pyramid. Are these two locations candidates for a new (secret) chamber? The probability that all these findings are based on combined accident is close to zero. The question, whether the Ancient Egyptians could have had this knowledge, is not discussed. Beside the description of the planetary correlation, this report is a user manual for the P4 computer program, enabling the corresponding astronomical calculations. For a better verifiability, it contains a listing of the entire Fortran source code.