Measuring for trim
Measure each wall at floor level, corner to corner. For a simple rectangle, the perimeter is 2 × (length + width). Subtract door openings, since baseboard stops at the casing. Include closets if they get baseboard. For crown molding, measure at the ceiling, and don't subtract doors. Enter 0 doors.
The calculation
Linear feet = perimeter − (doors × door width). Add waste for miters and offcuts, then pieces = length ÷ piece length, rounded up. A 12 × 12 ft room with one 36 in door has 45 ft of baseboard, which is 4 pieces of 16 ft with 10% waste.
Piece count isn't just total length ÷ piece length, though. Each wall needs its own pieces, and you can't join offcuts endlessly. Use the result as a minimum, and check the longest walls: a 14 ft wall wants one 16 ft piece rather than two short ones joined.
Trim for common rooms
| Room | Net length | Length with waste | 16 ft pieces | 8 ft pieces |
|---|---|---|---|---|
| 10 × 10 ft | 37 ft | 40.7 ft | 3 | 6 |
| 10 × 12 ft | 41 ft | 45.1 ft | 3 | 6 |
| 12 × 12 ft | 45 ft | 49.5 ft | 4 | 7 |
| 12 × 14 ft | 49 ft | 53.9 ft | 4 | 7 |
| 14 × 16 ft | 57 ft | 62.7 ft | 4 | 8 |
| 16 × 20 ft | 69 ft | 75.9 ft | 5 | 10 |
| Room | Net length | Length with waste | 4.2 m pieces | 2.4 m pieces |
|---|---|---|---|---|
| 3 × 3 m | 11.1 m | 12.2 m | 3 | 6 |
| 3 × 3.6 m | 12.3 m | 13.5 m | 4 | 6 |
| 3.6 × 3.6 m | 13.5 m | 14.9 m | 4 | 7 |
| 3.6 × 4.2 m | 14.7 m | 16.2 m | 4 | 7 |
| 4.2 × 4.8 m | 17.1 m | 18.8 m | 5 | 8 |
| 4.8 × 6 m | 20.7 m | 22.8 m | 6 | 10 |
Corners and joints
- Inside corners: many carpenters cope inside corners rather than mitering them, because a coped joint stays tight when walls aren't square.
- Outside corners are mitered. Each corner uses a little extra length.
- Long walls: join pieces with a scarf joint (overlapping 45° cuts) over a stud, rather than a square butt joint.
- Waste: 10% suits simple rooms. Use 15% for rooms with many corners, bump-outs or crown molding, where compound miters lead to more test cuts.
Worked examples
Bedroom, 12 × 14 ft, 1 door + closet opening (2 openings)Bedroom, 3.66 × 4.27 m, 1 door + closet opening (2 openings)
Room length 14 ft · Room width 12 ft · Door openings 2 · Door width 36 in · Piece length 16 ft · Waste / overage 10 %Room length 4.27 m · Room width 3.66 m · Door openings 2 · Door width 91.4 cm · Piece length 4.88 m · Waste / overage 10 %
- Pieces to buy: 4
- Net length: 46 ftNet length: 14 m
- Length with waste: 50.6 ftLength with waste: 15.4 m
Living room crown molding, 18 × 14 ft (no door deduction)Living room crown molding, 5.49 × 4.27 m (no door deduction)
Room length 18 ft · Room width 14 ft · Door openings 0 · Door width 36 in · Piece length 16 ft · Waste / overage 15 %Room length 5.49 m · Room width 4.27 m · Door openings 0 · Door width 91.4 cm · Piece length 4.88 m · Waste / overage 15 %
- Pieces to buy: 5
- Net length: 64 ftNet length: 19.5 m
- Length with waste: 73.6 ftLength with waste: 22.4 m
Whole floor, 1,000 ft² of rooms, ~260 ft of walls, 8 doorsWhole floor, 92.9 m² of rooms, ~79.2 m of walls, 8 doors
Room length 65 ft · Room width 65 ft · Door openings 8 · Door width 32 in · Piece length 16 ft · Waste / overage 10 %Room length 19.81 m · Room width 19.81 m · Door openings 8 · Door width 81.3 cm · Piece length 4.88 m · Waste / overage 10 %
- Pieces to buy: 17
- Net length: 238.7 ftNet length: 72.7 m
For a whole house, add up wall lengths from a floor plan. 2 × (65 + 65) = 260 ft is entered here as a stand-in.For a whole house, add up wall lengths from a floor plan. 2 × (65 + 65) = 79.2 m is entered here as a stand-in.
Buying and installing
- Buy the longest pieces you can transport. Fewer joints look better.
- Prime and paint trim before installing, and touch up afterwards. It's faster than cutting in along the floor.
- Nail into studs and the bottom plate. A stud finder helps on drywall.
- Shoe or quarter-round moulding covers the expansion gap on floating floors. It uses the same length as the baseboard.
- Paint the trim with the paint calculator, entering the trim area (length × board height).
Choosing baseboard
- MDF is smooth and inexpensive, and easy to paint. It swells if it gets wet, so avoid it in bathrooms and basements prone to dampness.
- Finger-jointed pine comes primed and is tougher than MDF at the edges. It's a good all-round choice for painted trim.
- Solid wood (oak, poplar and others) is for stained trim or matching existing woodwork.
- PVC or composite is unaffected by water, which suits bathrooms, laundry rooms and basements.
Height is a style choice. Taller baseboard suits rooms with higher ceilings. Whatever you pick, buy it all at once so the profile and colour match.
Common mistakes
- Counting pieces as total length ÷ piece length without checking the longest walls.
- Forgetting closets, hallways and stair skirts.
- Mitering inside corners on out-of-square walls. Coping hides gaps better.
- No allowance for test cuts on crown molding.
Shoe molding and quarter round
On hard floors, a small shoe molding or quarter round is often nailed to the base of the baseboard to hide the expansion gap at the edge of the floor. Floating floors need that gap, so the trim has to cover it. Shoe molding runs the same perimeter as the baseboard, so you can run this calculator a second time with the same room sizes and a 10% allowance. Some people skip it under cabinets or where the floor butts cleanly against tile. Nail shoe molding to the baseboard, not the floor, so a floating floor can still move.
Checked against
Each case below is re-run against the calculator by our automated test suite.
| Case | Our result | Checked against | Result |
|---|---|---|---|
| 12 × 12 ft room, one 36 in door: net length | 45 ft | Hand calculation | Match |
| Case | Our result | Checked against | Result |
|---|---|---|---|
| 3.66 × 3.66 m room, one 91.4 cm door: net length | 13.7 m | Hand calculation | Match |
Frequently asked questions
How much baseboard do I need for 1,000 square feet?
It depends on the room layout, not just area. Many small rooms mean much more trim. Add up the wall lengths from your floor plan and subtract the doors.
How do I calculate baseboard for a room?
Perimeter = 2 × (length + width). Subtract door widths, add 10% waste, and divide by the piece length.
Does crown molding need more waste?
Yes. Compound miters waste more, so 15% is a safer allowance.
How many pieces of 16 ft baseboard for a 12 × 12 room?
About 45 ft net with one door, which is 4 pieces of 16 ft including 10% waste.
Sources & assumptions
The results are planning estimates, and the cost figures only use prices you enter. Product yields, densities and coverage rates vary, so check the label or ask your supplier, and follow local codes. Figures marked "approximate" or "rule of thumb" are general practice, not exact standards.
See how we calculate and test our formulas and the changelog. Last updated 2026-10-08.
Reviewed by the MaterialWhiz Editorial Team. This estimate uses the assumptions shown in the calculator. Review the result against your supplier's product coverage and site conditions. Last reviewed: October 10, 2026. See how we calculate · Report a correction.