Number of Steps: The total risers in your staircase. The top "step" lands on the upper floor, so you'll have one fewer tread than risers.
Actual Riser Height: The exact height of each step after dividing total rise evenly. IRC residential code allows a maximum of 7¾ inches.
Tread Depth: The horizontal surface you step on, calculated using a comfort rule. IRC code requires a minimum of 10 inches for residential stairs.
Total Run: The horizontal distance the staircase occupies on the floor — important for planning the footprint and stringer length.
How This Calculator Works
You enter the total rise (floor-to-floor height in inches) and your preferred riser height. The tool rounds to the nearest whole number of steps, computes the actual riser by dividing total rise evenly, calculates tread depth using a simplified comfort formula (10 − riser ÷ 2), and multiplies tread depth by one fewer than the step count for total run. Always verify against your local building code.
Quick Questions
Why is there one fewer tread than riser?
The last riser brings you to the upper floor level, which serves as the final "tread." So a staircase with 14 risers has 13 actual tread surfaces plus the landing.
What riser height should I target?
Most building codes cap residential risers at 7¾ inches, but 7–7½ inches is the most comfortable range. Exterior deck stairs sometimes use 6–7 inches for a gentler climb.
What does building code require for treads?
The IRC (International Residential Code) requires a minimum tread depth of 10 inches and allows a maximum riser of 7¾ inches. The maximum variation between any two risers is ⅜ inch. Always check local amendments.
How do I measure total rise?
Measure from the finished surface of the lower floor to the finished surface of the upper floor. Include any flooring thickness that hasn't been installed yet — even a ¾-inch difference affects riser uniformity.