Wood & Trim
Baseboard Calculator
Estimate baseboard lengths from room perimeter, door openings and stock length.
Enter your measurements
Results update as you type.
About this calculator
Enter a room's dimensions (or a measured wall total), subtract door and other openings, and divide by the stock length you will buy. The result shows net length, order length with extra allowance, whole stock pieces and leftover.
How to use this calculator
- Measure the room, or measure the total wall length directly.
- Subtract the widths of doors and other openings.
- Enter the stock length sold at your supplier.
- Calculate for whole pieces, purchased length and leftover.
Formula
Perimeter = 2 × (length + width), or your measured total
Net length = perimeter − openings
Stock pieces = ⌈net × (1 + extra ÷ 100) ÷ stock length⌉
Assumptions
- A rectangular room in room mode; use measured total for irregular rooms.
- Openings cannot exceed the perimeter.
- Allowance applies once before counting pieces.
Common mistakes
- Subtracting windows that do not interrupt floor-level trim.
- Treating total linear length as an optimized room-by-room cutting plan.
- Forgetting corner, scarf-joint and defect allowances.
Worked example
Try it: press “Load example” above the form.
A 4 × 3 m room has a 14 m perimeter; less 0.9 m of door is 13.1 m, with 10% extra 14.41 m — 7 pieces of 2.4 m.
Limitations
No corner, cope or finish instructions. Measurement and purchasing math only.
Frequently asked questions
Should I subtract door widths?
Subtract the floor-level widths where trim will not be installed. Do not subtract windows above the trim or add the same opening twice.
Does total length optimize stock cuts?
No. Whole stock lengths round up from the total requirement. Corners, scarf joints, defects and room-by-room cut constraints can require additional pieces.
What does the worked example show?
A 4 × 3 m room has a 14 m perimeter; less 0.9 m of door is 13.1 m, with 10% extra 14.41 m — 7 pieces of 2.4 m.
Which assumptions should I check before using the result?
No corner, cope or finish instructions. Measurement and purchasing math only.
Sources
Sources explain the methods and any named product presets. Check your product label where coverage, yield or density differs.
Calculation documentation · Updated 2026-11-08 · Version 1.6.4. Estimates are planning aids. Confirm quantities, coverage and prices with your supplier before purchasing. Found an error? Report it.
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