Stair Calculator

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Design a safe, comfortable staircase with our Stair Calculator. Enter the total height (rise) and horizontal distance (run) between floors, plus your preferred riser height, and we'll tell you exactly how many steps you need, the precise tread depth, the slope angle, and the total stringer length.

Good stairs follow the 17-18 inch rule: one riser plus one tread should equal 17-18 inches for natural walking rhythm. Our tool checks your design against this guideline and alerts you if it's outside the comfortable range.

Formula
Number of risers = Total Rise ÷ Riser Height; Tread = Total Run ÷ (Risers − 1)

FAQ

What is the ideal riser/tread ratio?
Most building codes require risers between 4-8 inches and treads at least 10 inches. A comfortable rule of thumb: riser + tread ≈ 17-18 inches (e.g., 7" + 11" = 18").
How do I calculate stringer length?
Use the Pythagorean theorem: stringer = √(total rise² + total run²). The calculator gives you this automatically.

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