Header Size Calculator

💡 How to Size a Header

Headers carry loads above openings (doors, windows) to the jack studs on each side. For load-bearing walls, header size depends on the span width and number of stories supported. Non-bearing walls need only a flat 2×4 header for spans up to 6 feet.

Load-bearing headers (1 story): 4 ft span = doubled 2×6. 6 ft = doubled 2×8. 8 ft = doubled 2×10. 10 ft = doubled 2×12. For 2-story support, upsize by one or use LVL. Spans over 10 feet typically require engineered beams (LVL, glulam, or steel).