Stair Calculator: IRC Winders

Enter the numbers from your drawing. The app checks the stair against IRC R311.7 (2021), winders included, and draws the plan and the section. ■ Winders, measured the way the code does Winder treads must be at least 10 in at the walkline (12 in from the inside of the turn) and at least 6 in at any point, including the narrow end. Enter the depth at the narrow end and every winder is checked, together with winder uniformity (3/8 in), risers (7 3/4 in), treads (10 in), width (36 in, and 31 1/2 in or 27 in at handrail height), rise between floors or landings (12 ft 7 in) and handrails. ■ Feet, inches and sixteenths Type 9' 6 3/16", 9-6 3/16 or 114.1875 and they all mean the same. Results are shown to the nearest 1/16 in. ■ If your drawing numbers disagree, it says so first When riser × risers doesn't match the total rise, the app stops instead of giving a verdict and asks which number is…