Construction Tool

Stair Calculator

Calculate risers, actual riser height, treads, total run, stair angle, and stringer length with precise unit conversion and transparent geometry.

Planning note: This tool calculates stair geometry. Building-code limits vary by jurisdiction, stair type, occupancy, handrail/landing details, and project conditions. Verify final dimensions with the applicable local code and project requirements.
1Total Rise

Vertical finished-floor-to-finished-floor height.

2Riser Setup

Use a target maximum riser height, or enter the exact number of risers.

3Tread Depth (Run)

Horizontal run of each tread used for geometry.

Advanced Options
Optional planning checks. These do not certify code compliance.
Stair Geometry — Side View
Total RunTotal RiseStringer 102.00 in 130.00 inDynamic schematic — updates with riser count
Stair Calculation Results
Total Rise102.00 in8 ft 6 in
Number of Risers14whole risers
Actual Riser Height7.29 in18.51 cm
Number of Treads13straight stair assumption
Tread Depth10.00 in25.40 cm
Total Run130.00 in10 ft 10 in
Stair Angle38.1°atan(total rise ÷ total run)
Stringer Length165.41 in13 ft 9.41 in
Rise + Run Check24.57 in2 × riser + tread
Calculation Breakdown