Stair Size Calculator 2026

Stair Size Calculator is an offline utility for homeowners, carpenters, renovators, and self-build projects. It helps you quickly plan common stair layouts such as straight stairs and landing stairs. Enter floor height, available run, tread depth, target riser height, or step count, and the app calculates step count, riser height, tread size, horizontal projection, slope comfort range, and footprint reference. You can save multiple room or project plans for later checking. Key features: 1. Stair step calculation: calculate riser height, tread depth, horizontal run, and total footprint from floor height, total length, step count, or target riser height. 2. Comfort and risk hints: flag common issues such as high risers, narrow treads, steep slope, or insufficient clearance. 3. Plan templates: save stair plans by room or project, including straight stairs, stairs with landings, and narrow-space layouts. 4. Material and construction reference: estimate tread count, riser board count, handrail length, landing size, and on-site notes. 5. Units and reverse calculation: switch between millimeters, centimeters, and meters, and reverse-calculate floor height or suitable tread depth. No registration is required. The app works offline, does not connect to the internet, and does not collect personal data. All plans, notes, and calculation records stay on your device, making it practical for job sites, measurement visits, quotation discussions, and construction checks.