🚪 Door Header Size Calculator
Calculate header size for door openings
Width of the door opening (not including door frame)
Bearing walls require larger headers
How to Use This Calculator
Enter Opening Width
Input the width of your door opening in feet. This is the clear opening width where the door will be installed, not including the door frame width.
Select Building Type
Choose residential or commercial. Commercial buildings typically require larger headers for the same opening width due to different load requirements and building codes.
Specify Load Type
Choose standard (non-bearing wall) or bearing wall. Bearing walls support the structure above (roof, floors) and require larger headers. Non-bearing walls are interior walls that don't support loads.
Calculate and Verify
Click "Calculate Header Size" to see the recommended header size. For large openings (over 8-10 feet), the calculator will recommend consulting an engineer. Always verify with local building codes.
Header Sizing Guidelines
Header Size = Based on opening width, building type, and load requirements
Header Length = Opening Width + 3 feet (extends 1.5" past opening each side)
Large Openings (>8-10 ft) = Require engineered headers
Residential Header Sizing (Non-Bearing Walls):
• Openings up to 4 ft: Single 2×6
• Openings 4-6 ft: Single 2×8
• Openings 6-8 ft: Double 2×10
• Openings 8-10 ft: Double 2×12
• Openings over 10 ft: Engineered header required
Bearing Wall Headers:
• Bearing walls require one size larger than non-bearing walls
• Example: 6 ft opening in bearing wall needs Double 2×10 (instead of Single 2×8)
• Always verify with local building codes and engineering requirements
About Door Header Size Calculator
The Door Header Size Calculator is an essential tool for contractors, builders, carpenters, and DIY enthusiasts who need to accurately determine the correct header size for door openings in their construction projects. This calculator eliminates guesswork by providing precise header sizing recommendations based on opening width, building type, and load requirements, helping you install properly sized headers that meet building code requirements.
When to Use This Calculator
- New Door Installation: Calculate header size for new door openings in walls
- Door Replacement: Determine header size when replacing existing doors or enlarging openings
- Opening Enlargement: Verify header size when enlarging door openings
- Wall Construction: Plan header sizing during new wall construction or renovations
- Building Code Compliance: Ensure headers meet building code requirements for openings
Why Use Our Calculator?
- ✅ Accurate Sizing: Provides correct header sizes based on opening width and load requirements
- ✅ Building Code Guidelines: Based on standard building code header sizing requirements
- ✅ Load Types: Differentiates between bearing and non-bearing walls for proper sizing
- ✅ Multiple Building Types: Supports both residential and commercial building requirements
- ✅ Safety: Helps ensure headers are properly sized to support loads safely
- ✅ Time Savings: Instant calculations eliminate manual lookups and sizing charts
Common Applications
Residential Construction: Homeowners and contractors planning door installations use this calculator to determine the correct header size. Standard residential doors (30-36 inches wide) typically require 2×6 or 2×8 headers, which this calculator helps determine accurately.
Commercial Construction: Contractors and builders planning commercial door openings use this tool to estimate header sizes needed. Commercial buildings typically require larger headers for the same opening width due to different load requirements.
Remodeling Projects: Contractors and homeowners planning door openings in existing walls use this calculator to determine header sizes needed, ensuring proper structural support.
Tips for Best Results
- Check Local Codes: Header requirements vary by location—always verify with local building codes
- Bearing Walls: Bearing walls (supporting roof/floor above) require larger headers than non-bearing walls
- Large Openings: Openings over 8-10 feet typically require engineered headers—consult an engineer
- Header Support: Headers must be properly supported on both sides by studs or posts
- Permits: Structural changes often require building permits—check local requirements
Frequently Asked Questions
What size header do I need for a 6-foot door opening?
For a 6-foot door opening in a residential non-bearing wall, you'll need a single 2×8 header. For a bearing wall, you'll need a double 2×10 header. The header should extend 1.5 inches past the opening on each side (total length about 9 feet).
What's the difference between bearing and non-bearing walls?
Bearing walls support the structure above (roof, floors, loads from above). Non-bearing walls are interior walls that don't support structural loads. Bearing walls require larger headers to support the additional weight. Always identify wall type before selecting header size.
Do I need an engineer for large door openings?
Yes! Openings over 8-10 feet typically require engineered headers designed by a structural engineer. Large openings create significant structural loads that must be properly calculated and designed. Always consult with a licensed engineer for openings over 8 feet.
How long should a header be?
Header length should equal the opening width plus support on each side (typically 1.5 inches per side). For a 6-foot opening, header length is about 9 feet (6 ft + 1.5 ft + 1.5 ft). The header must be properly supported by studs or posts on both sides.
Can I use a single header instead of double?
For small openings (up to 4-6 ft), single headers are often sufficient. For larger openings (6+ ft) or bearing walls, double headers (two pieces) provide better strength and load capacity. Always follow building code requirements and use double headers when recommended.
Do header requirements vary by location?
Yes! Building codes and header requirements vary by location, climate, and building type. Always check local building codes for specific requirements. This calculator provides general guidelines—local codes may have different or more specific requirements.