Baseboard Calculator
Calculate the linear feet of baseboard molding needed for your room. Accounts for door openings.
Formula & Explanation
Baseboard (or base trim) is installed along the bottom of walls to cover the joint between the floor and wall. The calculation is straightforward: 1. Calculate room perimeter: Perimeter = 2 × (Length + Width) 2. Subtract door openings: Baseboard = Perimeter − Door Opening Width The result is expressed in linear feet. Standard door openings are 3 feet wide (36 inches). For multiple doors, add the width of each opening together.
Assumptions
- •Room is rectangular with perpendicular walls
- •Measurements are in feet
- •Standard interior door opening is 36 inches (3 feet) wide
- •Baseboard is installed on all walls except at door openings
- •Calculation accounts for inside corners (90° corners do not reduce length)
- •Basement stairs, closet entries, and large openings should be included in door opening total
- •Result is rounded up to the nearest foot
- •Waste factor for cuts and breakage is not included; add 5-10% for practical purchasing
- •This calculator does not account for room jogs, alcoves, or complex room shapes
Example Calculation
A 12ft × 10ft room has a perimeter of 44 linear feet. With one 3-foot door opening (standard entry door), you need 41 linear feet of baseboard.
Inputs
Results
Baseboard Quantity by Room Size
| roomSize | perimeter | oneDoorm | twoDoors |
|---|---|---|---|
| 10 × 10 ft | 40 ft | 37 ft | 34 ft |
| 10 × 12 ft | 44 ft | 41 ft | 38 ft |
| 12 × 12 ft | 48 ft | 45 ft | 42 ft |
| 12 × 15 ft | 54 ft | 51 ft | 48 ft |
| 15 × 20 ft | 70 ft | 67 ft | 64 ft |
Frequently Asked Questions
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