How the baseboard calculator works
Baseboard runs around the room at floor level and stops at door openings. The calculator subtracts the openings from the perimeter, adds your waste for miters and copes, and divides by the piece length, rounding up.
The outline diagram shows the run with the door gap, and the chart shows installed length, allowance, and the extra you get from whole pieces.
Formula and assumptions
- openings
- total width of doorways without baseboard
- piece length
- stock length you will buy
Assumptions and limits
- Rectangular room.
- Does not plan which piece goes on which wall.
Worked example
A 12 × 10 ft room, 6 ft of door openings, 8 ft pieces, 10% waste.
- Perimeter = 44 ft; net = 38 ft.
- 38 × 1.10 = 41.8 ft.
- 41.8 ÷ 8 = 5.23; round up to 6 pieces.
These are the calculator’s default values, so the live result above matches this example until you change an input.
How to measure correctly
- Measure each wall at floor level and note where doorways and cabinets interrupt the run.
- Buy pieces long enough to span most walls without a joint.
- Count outside corners; each needs a miter and adds waste.
Pieces for common rooms
| Room | Perimeter | 8 ft pieces | 12 ft pieces |
|---|---|---|---|
| 10 × 10 ft | 40 ft | 6 | 4 |
| 12 × 10 ft | 44 ft | 6 | 4 |
| 12 × 12 ft | 48 ft | 7 | 5 |
| 14 × 12 ft | 52 ft | 7 | 5 |
| 16 × 14 ft | 60 ft | 8 | 6 |
Baseboard Calculator FAQ
How do I calculate linear feet of baseboard?
Add the lengths of all walls (the perimeter) and subtract the width of door openings. A 12 × 10 ft room with one 3 ft door needs 41 linear feet before waste.
How much extra baseboard should I buy?
A 10–15% allowance is a common buffer for miters, copes, and mistakes. Rooms with many outside corners may need more.
What lengths does baseboard come in?
Lengths vary by product and store. Longer pieces mean fewer joints; enter the length you will buy.
Do I subtract cabinets and built-ins?
Yes, subtract any wall length where baseboard will not run, just like door openings.
Can I use this for shoe molding or quarter round?
Yes. It follows the same perimeter, so the count is the same calculation.