This app calculates how many studs you need to frame a wall, total nails/screws needed for the studs and estimates the number of boards you need for the top and bottom plates of the wall. The On Center (OC) spacing entered for the studs depends on the type of materials being used and local building codes. In the bottom of a 2x4 stud typically use two nails per side, opposite one another, crossing in the nailed-to member. In the bottom of a 2x6 stud use 3 (and in some cases 4) nails per side. For corner walls, you may need to add an extra stud on each end to provide additional support for drywall or plywood.'