Stair Calculator
Calculate stair dimensions, riser height, tread depth, and stringer length for safe staircase construction
Stair Dimensions
Enter the total rise and run for your staircase
Total vertical height of the staircase
Total horizontal distance of the staircase
Optimal range: 6-8.5 inches (15-22 cm)
Stair Calculations
Calculated dimensions and specifications
Enter stair dimensions to see calculations
Common Stair Scenarios
Click on a scenario to quickly set typical stair dimensions
Standard Interior Stairs
Rise: 108"
Run: 120"
Riser: 7.5"
Basement Stairs
Rise: 96"
Run: 108"
Riser: 8"
Deck Stairs
Rise: 30"
Run: 36"
Riser: 7.5"
Attic Stairs
Rise: 120"
Run: 100"
Riser: 8.5"
Stair Design Guidelines
Building Code Requirements
- • Maximum riser height: 8.25 inches (21 cm)
- • Minimum tread depth: 9 inches (23 cm)
- • Maximum variation between risers: 0.375 inches
- • Minimum headroom: 6 feet 8 inches (203 cm)
- • Minimum stair width: 36 inches (91 cm)
Design Tips
- • Use the 2R + T = 24-25 rule for comfort
- • Consistent riser heights prevent tripping
- • Steeper stairs take less space but are harder to climb
- • Consider handrail requirements for safety
- • Allow extra material for cuts and waste