Door Frame Materials Calculator
Calculate the jamb, casing, and shim materials needed for a door frame installation based on opening size.
Materials Needed
Door Frame Materials calculates what you need to frame a door opening.
Components:
- Jamb: Lines the inside of the opening (2 sides + 1 top = 3 pieces)
- Casing/Trim: Decorative frame around the door (2 sides + 1 top × 2 sides of wall = 6 pieces)
- Shims: For leveling and plumbing (pairs every 12–16 inches)
Jamb calculation:
- 2 side jambs = opening height + 0.25 inches each
- 1 head jamb = opening width + jamb thickness × 2
Casing calculation:
- Side casing length = opening height + 3 inches (for reveal + miter)
- Head casing length = opening width + 6 inches (for reveals + miters)
- Multiply by 2 for both sides of the wall
Standard door sizes:
| Door | Rough Opening |
|---|---|
| 24" | 26" × 82.5" |
| 30" | 32" × 82.5" |
| 32" | 34" × 82.5" |
| 36" | 38" × 82.5" |