Project estimates

Stair Calculator

Calculate the number of steps, riser height, tread depth, and stringer length for a staircase. Use this Construction and home tool to enter your numbers, review the result, and understand the key assumptions before making the next decision.

What you get
A focused calculator, clear explanation, common questions, and useful next tools.
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Calculator
Result
Explanation
Common questions
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How this calculator works
The result depends on the numbers you enter and the assumptions shown below.

Building code typically requires: riser height 7–7.75 inches, tread depth 10–11 inches. Rule of thumb: 2×rise + run = 25 inches. Stringer length = √(total rise² + total run²).

Review the inputs carefully and treat the output as an estimate. For decisions involving money, taxes, health, law, or security, compare the result with trusted professional guidance when needed.

Frequently asked questions

What is a comfortable stair rise and run?

A comfortable stair has a 7-inch rise and 11-inch run (tread). Building codes typically require risers between 4–7.75 inches and treads at least 10 inches.