Free estimate — verify against local code before building
Baseboard, Casing & Crown Molding Calculator
Turn room perimeters and openings into whole stock lengths, supplies, leftovers, and an editable material budget.
What this calculator includes
Add rectangular rooms, subtract door openings and intentional gaps, then include door casing, window casing, or crown molding. The calculator keeps installed linear feet, waste allowance, whole-stock rounding, purchased coverage, caulk, fasteners, paint, and cost separate so you can verify the order instead of relying on one rounded number.
How to use this baseboard & trim calculator
- 01
Add each room size
Measure length and width at the wall line. Use the quantity field for identical rooms and add a separate row when dimensions differ.
- 02
Subtract baseboard gaps
Enter each room's door count and average door width. Add cabinets, built-ins, fireplaces, or other no-baseboard runs in the excluded-length field.
- 03
Enter the stock and profile
Use the stock length and molding face widths you will actually buy. Waste covers miters, scarf joints, damaged ends, and pattern matching.
- 04
Verify the cutting plan
Whole-board rounding is based on total linear footage. Before ordering expensive or long-lead profiles, make a wall-by-wall cut list so short offcuts are not counted twice.
Calculation sources and review
Primary references and formula assumptions are linked so you can verify them against the selected product, supplier, and adopted local requirements.
Internal formula review completed July 13, 2026. What this review covers
- EPA — Renovation, Repair and Painting Program (opens in a new tab)
Lead-safe requirements when trim work disturbs paint in pre-1978 buildings.
- OSHA — Woodworking eTool (opens in a new tab)
Machine guarding, dust, and shop safety context for cutting trim.
Frequently asked questions
How much extra baseboard should I buy?
Ten percent is a useful starting allowance for simple rectangular rooms. Detailed profiles, many short walls, coped corners, pattern matching, and defects can require 12–15% or a wall-by-wall cut plan.
Do I subtract doors from baseboard measurements?
Yes. Baseboard normally stops at door casing, so subtract the rough or finished opening width for each door. Also subtract cabinets, built-ins, and other runs where baseboard will not be installed.
How is door casing measured?
The planning formula uses two vertical legs plus one head piece for each side of a door. Select one side or both sides and replace the default height and average width with your openings.
Does the board count guarantee my cut list will work?
No. It rounds total waste-adjusted linear feet to whole stock lengths. Long walls, joint placement, grain or pattern matching, and unusable offcuts can require another board, so verify a piece-by-piece cutting plan.