Header Size Calculator — Size Your Door and Window Headers Correctly

Header Size Calculator

Calculate the right header size for your door or window openings. Understand how span, load, and building codes affect header requirements.

Step 1: Opening Details

Understanding Header Sizing

Proper header sizing ensures structural integrity. Undersized headers can lead to sagging or structural failure, while oversized ones waste materials. The calculation considers span, load, and building code requirements.

Step 2: Additional Factors

1.0
1

About Load Factors

Load factor accounts for additional structural requirements. Standard residential construction typically uses 1.0, while commercial or high-load areas may require 1.2-1.5. Always consult local building codes for specific requirements.

Header Sizing Results

Summary
Header Comparison
Load Analysis

Recommended Header Size

2×10
Double with 1/2″ plywood spacer
Opening Width
36 inches
Total Load
1,250 lbs
Load Factor
1.0
Header Category
Medium

Header Size Comparison

Opening Type Width Recommended Header Load Capacity Material Cost

Load Requirement Analysis

Header Calculation Formula

Header Size = f(Span, Load, Material Strength, Safety Factor)

The header size is calculated using engineering formulas that consider span, total load, material properties, and safety factors. Actual requirements may vary based on local building codes, specific materials, and construction methods.

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