The experimental data about end thickness variation of tubes produced by PRP-80 of “Sinarskiy Pipe plant”are analyzed. The data of length of thickened ends of rough and finished tubes are shown. The configuration of thickened ends is displayed as conical shape with rectilinear generatrices, and the linear regression equations are obtained. The formula for calculating of length of front and back thickened ends are obtained. The data of thickness variation of rough and finished tubes are shown.