Baseboard and Trim Calculator
Pieces of baseboard or trim for a rectangular room, with door openings subtracted and 10 percent allowed for mitre cuts.
Results
Worked example
A 4 m by 5 m room has a perimeter of 18 m. One 0.9 m door opening leaves 17.1 m of trim. Adding 10 percent for mitres gives 18.8 m to buy, which is 8 pieces at 2.4 m each.
How it works
Perimeter = 2 × (length + width). Net trim = perimeter minus the total width of door openings. Buy length = net trim × 1.10 for mitre cuts and mistakes. Pieces = buy length ÷ piece length, rounded up. Closet openings and wide cased openings can be entered as openings too, using their real widths.
FAQ
Why add 10 percent?
Every inside and outside corner costs a mitre cut, and one miscut can consume a full piece. Ten percent covers normal waste on a rectangular room; rooms with many corners may need more.
Can I use this for crown moulding or shoe moulding?
Yes. The length math is the same for any linear trim run around the room. Calculate each profile separately since piece lengths can differ.
Estimates only. Mississippi Maple provides approximate material estimates for planning. Verify quantities with your supplier or contractor before purchasing.