Door Header Size Calculator
Determine the right header size for your door or window opening. Enter your span, building width, and load conditions to get the recommended dimensional lumber header per IRC guidelines.
Width of the door or window rough opening
Total width of the building perpendicular to the header
Number of stories supported by this header
Check local building code for your area snow load
What size header do I need for a 6-foot door?
A 6-foot door opening typically requires a 2×10 or 2×12 header depending on load conditions. For a single-story building with moderate snow load, a double 2×10 header is usually sufficient. For two stories or heavy snow loads, upgrade to a double 2×12. Always consult your local building codes as requirements vary by region and specific load conditions.
What is the difference between load-bearing and non-load-bearing headers?
Load-bearing headers support structural weight from above including roof, floors, and snow loads. Non-load-bearing headers (in interior partition walls) only support the wall itself and any door weight. Non-load-bearing openings up to 6 feet wide can use a single 2×4 flat or a 2×6 on edge. Load-bearing headers require engineered sizing based on span, building width, and loads above.
How do I determine if a wall is load-bearing?
A wall is typically load-bearing if: it runs perpendicular to floor joists, has another wall or structure directly above it, supports roof trusses, or is an exterior wall. Interior walls parallel to joists are usually non-load-bearing. Check the attic: if rafters or trusses rest on the wall, it is load-bearing. When in doubt, consult a structural engineer before removing or modifying any wall.
Can I use LVL beams instead of dimensional lumber for headers?
Yes, LVL (Laminated Veneer Lumber) beams are stronger and allow larger spans than dimensional lumber. An LVL header can span about 1.5 times farther than a dimensional lumber header of the same size. For example, a 1.75" × 9.5" LVL can span up to 10-12 feet for a single story, while a double 2×10 dimensional lumber might only span 6-7 feet under similar loads.