a. Take a narrow piece of straight stock, called a story pole, and mark on it the distance from the lower-floor to the upper-floor level. This is the lower-room height, plus the thickness of the floor joists and the rough and finished flooring. It is also the total rise of the stairs. Keep in mind that a flight of stairs forms a right triangle. The rise is the height of the triangle, the run is the base, and the length of the stringers is the hypotenuse.

b. Set dividers at 7 inches, the average distance from one step to another.

c. Step off this distance on the story pole.

d. Adjust the divider span slightly if this distance will not divide evenly into the length of the story pole. Step off this distance again.

e. Continue this adjusting and stepping off until the story pole is marked off evenly. The span of the dividers must be near 7 inches. This represents the rise of each step.

f. Count the number of spaces stepped off evenly by the dividers on the story pole. This will be the total number of risers on the stairs.

g. Measure the length of the stairwell opening for the length of the run of the stairs. Obtain this length from the plans. The stairwell-opening length forms the base of a right triangle. The height and base of the triangle have now been obtained.