Door Header Size Calculator
Determine the required header size for a door or window opening in a load-bearing wall.
Formula
Header size lookup by opening width and load type (IRC guidelines)
- Based on IRC Table R602.7 guidelines.
- Headers are typically doubled 2× lumber with 1/2-in plywood spacer.
- LVL beams recommended for spans over 6 ft or heavy loads.
3 ft door, single-story load
Inputs
- Opening Width: 3 ft
- Load Type: single
3 ft opening with single story load → 2 - 2×6 header.
Frequently asked questions
Do I need a permit to change a door opening?
Yes, for load-bearing walls. Always pull a permit and have the work inspected.