Structures

Stair Stringer & Step Calculator

Calculate step count, exact riser height, tread depth, total horizontal run, and 2x12 stringer board length.

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Input Parameters

Enter dimensions and specifications to estimate materials.

Instant
in
in (max 7-3/4")
in (min 10")
in
Real-time verified calculation
Your Result

Total Steps (Risers)

14Steps
Calculation Breakdown

Exact Riser Height

7.5"

Total Horizontal Run

136.5" (11.4 ft)

Stringer 2x12 Lumber Length

16 ft board

Stringers Required

3stringers

Incline Slope Angle

37.6°

Material estimates include recommended trade waste buffer. Always confirm dimensions on site prior to ordering.

How The Calculation Works

Formulas, material coverage assumptions, waste buffers, and rounding standards.

Number of steps is calculated by dividing total rise by the target riser height (7.5" is IRC ideal).

Exact riser height is computed by dividing total rise by step count, ensuring identical height for every step.

Stringer board length is calculated using the Pythagorean theorem: √(Total Rise² + Total Run²).

Standard Formula: Steps = Round(Rise / 7.5") | Run = (Steps - 1) × TreadDepth

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Frequently Asked Questions

Practical installation guidance and purchasing tips for stair stringer & step calculator.

Under the International Residential Code (IRC R311.7.5.1), the maximum riser height is 7-3/4 inches (196 mm), and the maximum variation between the highest and lowest riser is 3/8 inch.