Stair Calculator

Category: Housing/Building
- February 06, 2025
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Building Code Requirements:

  • Residential:
    • Maximum riser height: 7.75 inches
    • Minimum tread depth: 10 inches
    • Minimum stair width: 36 inches
  • Commercial:
    • Maximum riser height: 7 inches
    • Minimum tread depth: 11 inches
    • Minimum stair width: 44 inches

Stair Calculator

The Stair Calculator helps determine the number of steps, riser height, and tread depth required to build a staircase that meets building code regulations.

Formulas:

Number of Steps = Total Rise ÷ Maximum Riser Height

Riser Height = Total Rise ÷ Number of Steps

Tread Depth = Total Run ÷ (Number of Steps - 1)

How to Use the Stair Calculator

  • Enter the total rise (floor-to-floor height) in inches.
  • Input the total run (horizontal space available) in inches.
  • Select the building code type (Residential or Commercial).
  • Click "Calculate" to get the recommended stair dimensions.

Why Use a Stair Calculator?

  • Ensures stairs meet safety and building code regulations.
  • Helps plan staircase dimensions accurately.
  • Reduces construction errors and material waste.

FAQ

What is the maximum riser height for stairs?

For residential stairs, it is 7.75 inches. For commercial stairs, it is 7 inches.

How deep should each stair tread be?

Residential stairs require a minimum tread depth of 10 inches, while commercial stairs require at least 11 inches.

Can I customize the stair width?

Yes, but the minimum width must meet code requirements—36 inches for residential and 44 inches for commercial stairs.

How do I ensure my stairs are comfortable to use?

Follow the "7-11 Rule": riser height should not exceed 7 inches, and tread depth should be at least 11 inches for comfortable use.

Plan Your Staircase with Precision

Using this Stair Calculator ensures your staircase meets safety standards and fits your available space perfectly, making construction easier and more efficient.