Calculate linear feet, board count, and cost for your molding project — with waste factored in.
Enter your room's width and length in feet, then add any doorways or openings where molding won't be installed. Select your preferred board length and price, set your waste percentage, and click Calculate. The tool returns total linear feet needed, number of boards to buy, and an estimated material cost — instantly.
Use the tabs to calculate baseboard only, crown molding only, or both at once for a full room estimate.
Buying too little molding means a second trip to the hardware store — and worse, a potential color or texture mismatch between production batches. Buy too much and you're wasting money on materials you'll never use. A precise calculation upfront saves both time and cash.
Consider a typical 12×14 ft bedroom with one doorway (3 ft wide). The net perimeter is about 49 linear feet. With a 10% waste factor and 12-ft boards at $8.50 each, you'd need 5 boards for baseboard and another 5 for crown — roughly $85 total in materials before installation. Without a calculator, most people guess 6–8 boards and either run short or have 2 leftover pieces they can't return. Interior trim work accounts for a surprising amount of the "finishing" cost on remodels — getting the count right matters.
Step 1 — Net Linear Feet: Add room width + room length, multiply by 2 (perimeter), then subtract any door/opening widths.
Net LF = (2 × Width + 2 × Length) − Σ Opening Widths
Step 2 — Add Waste: Multiply net LF by (1 + waste %). This covers miter cuts, off-cuts, and mistakes.
Total LF = Net LF × (1 + Waste%)
Step 3 — Board Count: Divide total LF by board length, then round up to the nearest whole board.
Boards = ⌈ Total LF ÷ Board Length ⌉
Step 4 — Cost: Multiply board count by price per board.
For baseboard, yes — subtract the width of closet openings since baseboard doesn't span a doorway. Crown molding, however, typically returns at the top of the door casing rather than stopping, so crown deductions can be different. This calculator uses the same deduction for simplicity — adjust manually for crown if needed.
Set it to 15–20% if you're new to cutting and installing molding. Miter saw errors, miscuts on angles, and learning the coping technique all burn through material faster than expected. An extra board or two is cheap insurance compared to a second trip mid-project.
12-ft boards produce fewer seams in a typical room, which looks better and is structurally stronger. However, 8-ft boards are easier to transport if you don't have a truck. If a wall is longer than 8 ft, you'll need a scarf joint anyway — so go with 12-ft when possible.
The waste percentage accounts for the extra material consumed at miter and cope cuts. For rooms with many outside corners (like bay windows or diagonal walls), bump the waste to 20%. Standard rectangular rooms are fine at 10–12%.