Stair Calculator

Calculate stair dimensions and check building code compliance.

Measurements

Total Rise (Floor to Floor)

inches

Total vertical height from bottom to top floor

Available Run (Optional)

inches

Leave empty to calculate optimal run

Preferred Riser Height

inches

Typical range: 7-7.75 inches

Building Code Requirements (IRC)

Maximum Riser Height7.75 inches

Minimum Riser Height4 inches

Minimum Tread Depth10 inches

Maximum Stair Angle~42°

Minimum Width36 inches

Headroom80 inches minimum

Stair Design Formula

2R + T = 24-25 inches

Where R = riser height and T = tread depth. This formula ensures comfortable stairs that match a natural stride.

Stair Dimensions

Number of Steps13

Riser Height7.38" per step

Tread Depth10.23"

Total Run122.77"

Stringer Length155.85"

Stair Angle38°

Meets Building Code