The Staircase Online

: The sum of two risers plus one tread should equal approximately 25 inches .

: Fold a sheet of paper in half. Draw parallel lines perpendicular to the fold and cut them. Push the cut sections forward to create steps that "pop out" when the card opens. You can find detailed steps and templates on DIY.org . The Staircase

If you are making a realistic model, keep these standard architectural ratios in mind: : The sum of two risers plus one