The lateral loading pile problem is frequently solved by assuming that the pile is an elastic element and that the soil may be represented by a sequence of nonlinear horizontal springs. The P-y curves illustrate the soil springs' nonlinear behaviour. There are many ways, in literature and adopted in codes to calculate the displacement, ultimate, and allowable lateral load resulting from applying horizontal forces on a vertical pile. The aim of this study is to determine which codes and equations give the most accurate result in ultimate and allowable lateral load for available measurements and case studies. A study was conducted on 40 field and laboratory experiments under different soil conditions and different locations. The Egyptian, Canadian, British standard, AASHTO, DIN 4014 and Indian standards, as well as the Jean-Louis-Briaud method were used to determine the ultimate, and allowable lateral load values and compare them with field and laboratory measurements. The Canadian, British standard, and AASHTO, use broom's method to calculate ultimate, and allowable lateral load [1] [2] [3] .
German code uses an approximate method to find the maximum lateral displacement of 2cm or equal to 0.03D [4] .