On the stringer material, mark off the stair stringer tread cumulative diagonal marks. Using the stair stringer cumulative diagonal marks to layout the stringer risers and treads. This will help with the cumulative math error of only using a framing square to layout the risers and treads.
If the total diagonal length of the stair stringer is longer than the theoretical diagonal length , it will make the nose of the stair stringer tread out of level. The nose will be higher than it should be.