How to Calculate Stair Dimensions

Building stairs requires careful planning to ensure safety and comfort. Our stair calculator simplifies the process by automatically calculating all the necessary dimensions based on a few key measurements you provide.

Key Stair Measurements:

• Total Rise: The vertical height from the lower floor to the upper floor.
• Total Run: The horizontal length of the stairway (optional – will be calculated if not provided).
• Rise per Step: The height of each individual step (recommended between 7-7.75 inches).
• Run per Step: The depth of each step (recommended between 10-11 inches).

Stair Building Codes and Safety Standards

When building stairs, it’s important to follow local building codes which typically require:

• Consistent rise and run measurements for all steps
• Minimum headroom clearance of 80 inches
• Stair width of at least 36 inches for residential buildings
• Maximum rise of 7.75 inches and minimum run of 10 inches
• Handrails on at least one side if there are more than 3 steps

Types of Stairs

There are several common stair types you can build:

• Straight Stairs: The simplest design with steps going straight from one floor to another.
• L-Shaped Stairs: Include a landing and change direction by 90 degrees.
• U-Shaped Stairs: Include two landings and change direction by 180 degrees.
• Spiral Stairs: Compact design that winds around a central pole.

Stair Building Tips

• Always double-check your measurements before cutting materials
• Use quality lumber for stringers (typically 2×12 boards)
• Consider adding a nosing (1-1.5 inch overhang) for better footing
• Ensure proper lighting, especially for basement stairs
• Install non-slip treads for outdoor stairs or high-traffic areas