The Great Pyramid of Giza's is a well known ancient building on the outskirts of Cairo and its internal architecture contains a series of passages, shaft and chambers. Its upper chamber, commonly known as the King's Chamber, is constructed from polished granite blocks which are assembled with a high degree of precision, and as a result contain horizontal and vertical wall joints with thicknesses in the sub­millimeter range.

In this paper I show that the vertical joints between the granite wall blocks of the upper chamber have been designed so that they can be read as binary ones when set into a regular grid pattern of rectangles covering the wall.

I then show that this binary data is formatted in an identical manner to our contemporary IEEE 754 floating point number storage system for 16 bit computers and subsequently decode the numerical data on the chamber's north and west walls. I show that the numerical data that is extracted from the top two levels of the walls specifies the binary format of the system required to decode the numbers and then show that the decimal numbers obtained from the lower three levels of the walls describe recognisable features within the pyramid.