Stair Calculator

Estimate number of steps, step rise, step run, total run needed, and stringer length from total rise and total run. The calculator works in inches and checks the result against its built-in recommended rise and run ranges.

How to use this calculator

Enter total rise, which is the vertical floor-to-floor height, and total run, which is the available horizontal stair space. The result shows the number of steps, each step height, each tread depth, total run, and stringer length.

Formula

The number of steps is based on the maximum recommended rise:

$steps = ceiling(total\ rise \div 8)$

Then each step is:

$step\ rise = total\ rise \div steps$

For a 96 inch total rise and 132 inch total run, the calculator returns 12 steps. Each step rises 8 inches, each run is 11 inches, and stringer length is about 163.22 inches.

Building notes

Use the result for planning, then verify local stair code, landings, handrails, headroom, nosing, and actual tread layout. For concrete stairs, compare volume with the concrete calculator. For nearby flooring area, use the square footage calculator.