Stair Calculator

Calculate rise and run for building stairs. Determine stringer length, angle, and number of steps.

Total Rise (Height)

Floor to Floor height (in)

Desired Riser Height

Standard is ~7-7.75 in

Tread Run (Depth)

Standard is ~10-11 in

Construction Details

Number of Risers:15

Exact Riser Height:7.200"

Total Run (Length):140"

Stringer Length (Approx):176.8"

Not to scale

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Build Safe, Code-Compliant Stairs

Stair math is unforgiving! Our Stair Calculator helps carpenters and DIYers design safe, comfortable staircases. Simply measure the total vertical height (rise) from floor to floor, and this tool calculates the exact number of steps, individual riser height, and total run required. It ensures all steps are identical height—a critical safety requirement to prevent tripping.

Stringer Layout Helper

Cutting stringers is the hardest part of stair framing. This calculator provides the essential dimensions: the hypotenuse (stringer length) and the step angle. It automatically checks if your desired riser/tread dimensions fall within standard building codes (typically ~7" rise and ~10-11" run). Plan your layout before you cut your first piece of expensive lumber.

Safety Fact: A variation of just 1/4 inch between step heights is enough to cause people to trip! Our brain memorizes the step rhythm instantly, so consistency is key.

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