The calculation
Door casing = two legs + one head per side
Stock pieces = cut-list packing into full stock lengths, with the waste allowance used as a minimum purchase check
- Measure the installed jamb opening rather than relying only on nominal door size.
- Mitered long-point dimensions include the casing face width at the corner.
- Each required cut must fit inside the selected stock length; the calculator flags stock that is too short.
- The purchase count respects individual cut fit and the selected overall waste allowance.