Directional drilling has become a very importanttool in the development of oil and gas deposits. Currentexpenditures for hydrocarbon production have dictated thenecessity of controlled directional drilling to a much largerextent than previously. For a successful drilling operation to becarried out surveys, planning and calculations needs to becarried out at the start before the operation commences. Thepaper focusses on the design of well trajectory. In welltrajectory the well profile is plotted with the help of givenTarget and Surface Coordinates, Build-Up Rate, KOP. Thedocument has included the methods and formulas used forcalculation of Well Trajectory