Stair Calculator — Calculate Stair Dimensions & Requirements

Stair Calculator

Calculate stair dimensions, riser height, tread depth, and total run for your construction or remodeling project. Ensure code compliance and safety with accurate measurements.

Step 1: Basic Dimensions

105 in
120 in

Building Code Guidelines

Most residential codes require riser heights between 4-7.75 inches and tread depths of at least 10 inches. The ideal relationship is 2×Riser + Tread = 25 inches.

Step 2: Detailed Specifications

Stair Safety Tips

All steps should have uniform riser height and tread depth to prevent tripping. Consider adding handrails if stairs have more than 3 risers, and ensure proper lighting.

Stair Calculation Results

Summary
Stair Comparison
Visualization

Riser Height

7.0 in
Based on 105″ total rise and 15 steps
Number of Steps
15
Tread Depth
10 in
Total Run
150 in
Stair Angle
35.5°

Compliance Check

✓ These dimensions meet standard residential building code requirements for riser height and tread depth.

Stair Type Comparison

Stair Type Max Riser Min Tread Typical Use

Code Requirements

Building codes vary by location. Always check local regulations before construction. The International Residential Code (IRC) specifies maximum riser height of 7.75″ and minimum tread depth of 10″.

Stair Visualization

Visual representation of your stair dimensions (not to scale).

Stair Calculation Formulas

Number of Steps = Total Rise ÷ Riser Height

To calculate number of steps: Divide total rise (floor to floor height) by desired riser height. Round up to nearest whole number, then recalculate actual riser height.

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