NOT a structural design calculator. Rough reference table for common header sizes in residential construction. Always consult a licensed structural engineer and building code for actual design.
Last updated: March 2026
🚨 CRITICAL — DO NOT USE FOR ACTUAL CONSTRUCTION: This is an educational reference table ONLY. It uses simplified breakpoints and does NOT account for:
inches
feet
affects header size requirements
A structural header (or beam) is a horizontal member that spans across an opening (door or window) in a load-bearing wall to transfer weight from above down to the supporting jack studs. Headers are typically made of doubled or tripled 2×6, 2×8, 2×10, or 2×12 lumber, sometimes with metal plates or LVL (laminated veneer lumber) for added strength.
The size required depends on three factors: opening span (width), load type (whether the wall carries roof/floor loads), and building width (affects tributary load). Building codes (IRC/IBC) specify minimum sizes. Proper header sizing ensures the wall won't settle, sag, or crack, maintaining structural integrity and protecting drywall and finishes above the opening.
Sizing a header for a 36-inch door opening in a bearing wall with one floor above (typical home):
No. Building codes require minimum header sizes to prevent structural failure. Using an undersized header risks wall settlement, sagging, drywall cracks, and potential safety hazards. Always follow code minimums.
Jack studs support and bear the header weight directly. King studs are full-height studs on the sides that support jack studs. A typical opening has one king stud and one or two jack studs per side.
Not typically. Building codes specify doubled (or tripled) lumber headers, as the load distribution and connection requirements are different. Use sizes specified in tables for your opening and load condition.
Larger openings require engineered solutions: steel beams, LVL beams, or built-up beams with metal plates. Hire a structural engineer to design a custom header for very large spans.
Yes. All window and door openings in load-bearing walls require headers. Non-bearing walls can sometimes use simpler cripple studs over windows, but building codes still often require headers for structural support.
Rough opening is the size the framer builds (e.g., 36" wide for a 32" door). Finished opening is what the door/window fits into after trimming. Headers span the rough opening, which is 1-1.5 inches larger than the door.
No. Headers must be installed horizontally with proper bear at both ends. Incorrect installation compromises load transfer and can lead to failure. Always follow building code framing requirements.
If drywall above the opening is cracking, the door sticks, or there's visible sagging, the header may be undersized. Hire a building inspector or structural engineer to assess. Never remove or modify an existing header without professional guidance.