Design stairs with proper dimensions and building code compliance
Our Stair Calculator helps you design stairs with optimal dimensions. Enter your total rise and run, and optionally a desired riser height or tread depth, and the calculator will determine the number of steps, actual riser height, tread depth, and stringer length. It also validates your design against standard building codes.
Proper stair design is critical for safety and comfort. Building codes typically require riser heights between 4 and 7 inches and tread depths between 10 and 11 inches.
Most building codes require riser heights between 4 and 7 inches (typically 7 inches is standard for residential stairs). All risers on a flight of stairs must be within 3/8 inch of each other for consistency and safety.
The minimum tread depth is typically 10 inches for residential stairs per IRC (International Residential Code) standards. Some commercial codes require 11 inches. Nosing projection of 3/4 to 1-1/4 inches is also commonly required.