Stair Calculator - CalcHub

Plan Your Perfect Staircase

Calculate step counts, riser heights, and stringer lengths for straight stairs.

ft in

Vertical distance from the lower floor to the upper floor surface.

Step Settings

in

Standard is ~7.5" (19cm). Max is usually 7.75".

in

Standard is 10" to 11" (25-28cm).

Enter measurements

Enter total rise to see the step layout.

Terminology

  • Total Rise: The total vertical height from the surface of the lower floor to the surface of the upper floor.
  • Total Run: The horizontal distance the staircase will cover.
  • Riser: The vertical board between steps. Ideally between 7" and 7.75".
  • Tread: The horizontal board you step on. Ideally minimum 10".

The 17-18 Rule

A common rule of thumb for comfortable stairs is that the Rise + Run should equal roughly 17 to 18 inches (43-46cm).

Example: If you have a 7.5" riser, a 10" tread is perfect (7.5 + 10 = 17.5). If your riser is shorter, your tread should be deeper.

Frequently Asked Questions

What is the standard angle for stairs?

Standard staircases usually have an angle (pitch) between 30° and 42°. A comfortable angle is typically around 37°. Anything steeper than 42° is often considered a ladder or requires special "ship's ladder" design.

Why is my Total Run shorter than expected?

The Total Run is calculated based on the number of treads. Usually, there is one fewer tread than there are risers, because the final step up puts you onto the upper floor itself. This calculator assumes the standard N-1 tread rule.

How do I measure Total Rise accurately?

Measure from the finished surface of the bottom floor to the finished surface of the top floor. If you haven't installed flooring yet (like tile or hardwood), be sure to add the expected thickness of the flooring to your measurement.