Draw a tape measure straight up and down between the floors that the staircase will span; the distance between the floors is the staircase's total rise. Divide the total rise by the rise of an individual stair to determine the total amount of treads. Carpenters generally choose 7 inches as a stair height because a rise of roughly 7 inches and run of roughly 11 inches (run referring to the distance the stair travels) places the staircase at a comfortable 30-degree-to-35-degree angle.
Round the result of the calculation up or down to achieve a whole number of stairs. For example, a total rise of 36 inches divided by 7 equals approximately 5.14 stairs, which rounds down to 5 treads. Multiply the number of treads by 11 inches to determine the total run (distance traveled) of the staircase. For example, 5 treads multiplied by 11 inches equals 55 inches.
Divide the total rise of the staircase by the revised number of treads to determine the final rise of each riser. For example, a total rise of 36 inches divided by 5 steps equals 7.2 inches rise per step, or roughly 7 13/64 inches on a standard tape measure. Use the determined values of each stair's rise and run to lay out cut marks on stringer framing lumber.