How Much Baseboard and Trim Do I Need? Boards by Room Size
Part of the project planner: Planning to paint a room or a house.
A 12 × 14 ft room with two 3 ft doorways has 52 ft of wall, so it needs 46 linear feet of baseboard (net of the doorways) and, with 10% for waste, 7 boards of 8 ft. Crown molding goes around the whole perimeter: 8 boards. The baseboard and trim calculator works it out for your own room, doors and board length.
Baseboard for common rooms
With 3 ft doorways and 10% waste, in boards of 8 ft:
| Room | Perimeter | Baseboard net of doors | Boards of 8 ft | Crown boards of 8 ft |
|---|---|---|---|---|
| 10 × 10 ft (1 door) | 40 ft | 37 ft | 6 | 6 |
| 10 × 12 ft (2 doors) | 44 ft | 38 ft | 6 | 7 |
| 12 × 14 ft (2 doors) | 52 ft | 46 ft | 7 | 8 |
| 14 × 16 ft (2 doors) | 60 ft | 54 ft | 8 | 9 |
| 16 × 20 ft (3 doors) | 72 ft | 63 ft | 9 | 10 |
| 20 × 24 ft (4 doors) | 88 ft | 76 ft | 11 | 13 |
How to measure
- Measure each wall along the floor, and add them up for the perimeter.
- Subtract the width of each doorway or opening where there is no baseboard.
- Add 10% for waste and the angled cuts at the corners.
- Divide by the board length and round up. Plan which walls each board will cover to minimize the joints.
Choosing and installing trim
- Height: 3¼ to 5¼ inches is common for baseboard. Taller baseboard suits high ceilings.
- Material: MDF is cheap and smooth for painting, pine is paintable or stainable, and finger-jointed pine is a good value.
- Prime and paint first if you can: it is easier before the trim is nailed up.
- Nail into the studs with a finish nailer, fill the holes, caulk the top edge, and paint.
- Joints: cope the inside corners and miter the outside ones. Join long walls with a scarf joint over a stud.
See the paint calculator for the paint, and the area calculator for the room. Estimates only: confirm the quantities with your supplier.
Frequently asked questions
How do you calculate baseboard?
Add up the length of every wall in the room (the perimeter), take off the width of doorways, add 10% for waste and corners, and divide by the length of the boards. A 12 × 14 ft room with two 3 ft doors is 46 ft net, 50.6 ft with waste: 7 boards of 8 ft.
How much extra baseboard should I buy?
10% for a simple room, and 15% for a room with many corners or if you will cope the inside corners. Buy longer boards (12 or 16 ft) to cut fewer joints.
How much crown molding do I need?
The full perimeter (doors do not matter): 52 ft for this room, which is 8 boards of 8 ft with 10% waste.
Should I buy 8, 12 or 16 foot baseboard?
Longer boards mean fewer joints. Choose lengths that fit your longest walls so that most walls are one piece, and use the scraps on short walls.
How do you join baseboard in a corner?
Cope the inside corners (cut one board to fit the face of the other) and miter the outside corners at 45 degrees. A coped joint stays tight when the wood moves.
More guides
Tools & materials for this project
Affiliate links As an Amazon Associate we earn from qualifying purchases. These links do not change what you pay.
Estimates only. Quantities depend on your materials, site and supplier. Confirm important numbers before you order, and follow local building codes for anything structural.