Trim & Baseboard Calculator
Enter your room dimensions, door and window count, and waste preference to calculate exactly how many linear feet of baseboard, crown molding, door casing, and window casing you need — plus the number of 8-foot and 12-foot boards to buy.
Please enter valid room length and width values greater than 0.
How to Use This Calculator
- Measure your room. Enter the length and width of the room in feet. For non-rectangular rooms, break the space into rectangles and combine the perimeters — or measure the total wall run directly with a tape measure.
- Count openings. Enter the number of interior doors and windows in the room. The calculator deducts approximately 3 feet of baseboard per door opening and adds 17 linear feet of casing per door and 16 linear feet per window.
- Add crown molding if needed. Select "Yes" to include crown molding. Crown runs the full perimeter since it meets at inside and outside corners rather than stopping at door openings.
- Set your waste factor. Use the slider to choose between 5% (simple rectangular room, experienced installer) and 20% (complex room with many angles or first-time DIY). A 10% default suits most projects.
- Read your results. Each trim category is listed separately so you can price them independently. The board counts help you translate linear feet into a hardware store order.
How Trim Quantities Are Calculated
- Room perimeter:
2 × (length + width) = total linear feet - Baseboard:
(perimeter − doors × 3 ft) × (1 + waste ÷ 100) - Crown molding:
perimeter × (1 + waste ÷ 100) [if selected] - Door casing:
doors × 17 lin ft × (1 + waste ÷ 100) - Window casing:
windows × 16 lin ft × (1 + waste ÷ 100) - Total & board counts:
total lin ft ÷ 8 (8 ft boards) · total lin ft ÷ 12 (12 ft boards), each rounded up
Door casing uses 17 linear feet per door (both sides, including head piece). Window casing uses 16 linear feet per window. Crown molding runs the full perimeter because it wraps inside corners rather than stopping at openings.
Pro Tips
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Recommended Products for This Project
Metrie 3.5" Colonial Base Molding — 8 ft MDF
Popular painted colonial profile in pre-primed MDF.
View on Amazon →WM 366 Colonial Stop Casing — 8 ft Pine
Classic door and window casing in finger-jointed pine.
View on Amazon →Fypon 4.5" Crown Molding — 8 ft Polyurethane
Lightweight, paintable foam crown for easy DIY install.
View on Amazon →Bostitch 18-Gauge Brad Nailer Kit
Reliable finish nailer for baseboard and casing.
View on Amazon →Frequently Asked Questions
How many linear feet of baseboard do I need for a 12 × 14 room?
A 12 × 14 room has a perimeter of 52 linear feet. With one standard 32-inch door opening deducted (approximately 3 feet), you need about 49 linear feet of baseboard before adding a waste factor. At 10% waste, plan on 54 linear feet — which rounds to seven 8-foot boards or five 12-foot boards.
How much linear footage does a door casing set require?
A standard interior door casing set (two side legs and one head piece) requires approximately 16–17 linear feet of casing per door. This accounts for the two side legs at about 7 feet each and the head piece at about 3 feet, plus the mitered or square-cut returns at the floor. This calculator uses 17 linear feet per door set to include a small waste buffer.
Should I use MDF or solid wood baseboard?
MDF (medium-density fiberboard) trim is the most common choice for painted applications because it is stable, takes paint exceptionally well, and costs less than solid wood. It does not expand or contract with humidity like wood does, so joints stay tight. However, MDF is not suitable for areas prone to moisture (bathrooms, laundry rooms) because it swells when wet. Solid wood is the right choice for stained or natural finishes and for high-moisture areas.
What is the difference between baseboard and base cap molding?
Baseboard is the primary flat or profiled strip that runs along the base of the wall and covers the gap between the finished floor and the wall. Base cap molding is a smaller decorative piece nailed to the top edge of the baseboard to add visual complexity — it is only needed if you are using a flat baseboard profile and want a more traditional, layered look. Most modern baseboards have a profile built into the top edge and do not require a separate base cap.