Free Stair Calculator - Construction Made Easy
Calculate stair dimensions including rise, run, number of steps, and stringer length. Ensure building code compliance for safe, comfortable stairs.
Quick Answer
Standard stairs: 7" rise, 10-11" run. For 9 ft height: about 15-16 steps. Comfort formula: 2(rise) + run = 24-25 inches.
Key Facts about Stair Calculator:
- Standard rise: 7-7.75 inches
- Standard run: 10-11 inches minimum
- All steps must be equal height
- 2(rise) + run ≈ 24-25 inches
- Stringer = √(rise² + run²)
Why Use Our Stair Calculator?
Complete stair calculations:
Rise & Run
Optimal dimensions.
Step Count
Number of steps needed.
Stringer Length
Calculate stringer cut.
Code Check
Building code compliance.
Instant Results
Get dimensions immediately.
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Your data stays private.
How to Stair Calculator in 3 Easy Steps
Calculate stairs:
Enter Height
Total rise to climb.
Set Parameters
Preferred rise/run.
Get Dimensions
See all stair specs.
Build Safe Stairs
Code-compliant design
Comfortable steps
Accurate measurements
Safe construction
Common Use Cases for Stair Calculator
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Frequently Asked Questions
Everything you need to know about our stair calculator
What is the ideal stair rise and run?
Rise: 7-7.75", Run: 10-11". Ideal: 7" rise, 11" run
Code typically requires: rise 7-7.75 inches, run 10-11 inches minimum. Ideal comfort: 7" rise, 11" run. Formula: 2(rise) + run should equal 24-25 inches.
How many steps do I need?
Total rise ÷ 7" ≈ number of steps
Divide total rise by ideal step height (7-7.5"). For 9 feet (108"): 108/7 = 15.4, so 15 or 16 steps. Then calculate exact rise per step.
How do I calculate stringer length?
Stringer = √(rise² + run²)
Use Pythagorean theorem: √(total rise² + total run²). For 9' rise and 12' run: √(81 + 144) = √225 = 15 feet stringer length.
Still have questions? Try the tool yourself!
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