Work out riser height, tread depth, stair angle, and stringer length from total rise, total run, and riser count.
| Riser | – |
| Tread | – |
| Angle (°) | – |
| Stringer | – |
Use this calculator to lay out a straight stair before you cut stringers. Enter the floor-to-floor height, the total going, and how many risers you want.
Riser height = total rise ÷ risers. Tread depth = total run ÷ (risers − 1). Angle = arctan(rise ÷ run). Stringer length is the hypotenuse √(rise² + run²). Rise and run can be entered in metres (m) or feet (ft); they are converted to metres first. Riser and tread are shown in millimetres (mm) or inches (in), following the length unit you picked. The stringer is in m or ft.
This is a geometric layout. It does not check building-code limits on riser, tread, or nosing, and it is not a spiral or winder stair.
Total rise: Floor-to-floor height, in m or ft.
Total run: Horizontal going from first to last riser, in m or ft.
Risers: Number of risers. Treads are one fewer than risers.
Riser: Height of each riser.
Tread: Going of each tread.
Angle: Pitch of the stair in degrees.
Stringer: Length of the diagonal stringer.
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