Baseboard Calculator

Work out how much baseboard or trim you need for a room. Enter the dimensions and door openings to get the linear feet and the number of stock-length boards, with a waste allowance.

Baseboard calculator

Room length (ft) Room width (ft)

Door openings (ft) Board length (ft) Waste %

Subtract the total width of door openings (they get no baseboard). The waste allowance covers miter cuts at corners — add more for rooms with lots of corners.

How it's calculated

We take the room perimeter (2 × length + 2 × width), subtract the door openings, add your waste percentage for miter cuts, and divide by your board length — rounding up to whole boards.

Frequently asked questions

How much baseboard do I need?

Add up the room perimeter, subtract the door openings, add about 10% for cuts and miters, then divide by your board length. Enter your numbers above.

How do I measure for baseboard?

Measure the perimeter of the room (twice the length plus twice the width) and subtract the total width of door openings, which do not get baseboard.

How much extra baseboard for waste?

About 10% for straight rooms; more for rooms with many corners and miter cuts.

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Last updated June 2026.