Stair Rise & Run

Building safe residential stairs requires balancing total vertical rise with comfortable step dimensions that conform to local building code standards. Carpenters and homeowners must determine the exact riser height and tread depth to ensure uniform steps that prevent tripping hazards between floor levels. Entering total vertical rise, target riser height, and tread run calculates the required number of risers, exact step height, total horizontal run, stringer length, and pitch angle.

Interpreting the calculated riser height ensures the planned staircase falls within typical residential building codes, which generally mandate maximum riser heights of seven and three-quarter inches and minimum tread runs of ten inches. Maintaining a stair pitch angle between thirty and thirty-seven degrees delivers an ergonomic and safe walking ascent. One critical caveat is that finished flooring thicknesses at the top and bottom landings must be factored into stringer cuts, or the bottom and top steps will be uneven.

The number of risers is calculated by dividing total vertical rise by the target riser height and rounding to the nearest whole integer. Actual riser height is found by dividing total rise by this step count, while total run equals tread depth multiplied by risers minus one. The stringer length and pitch angle are derived using the Pythagorean theorem and trigonometry on the total rise and run.