Baseboard & Trim Calculator
Calculate the linear feet of baseboard or trim you need from the room perimeter, door openings to subtract, a waste factor, and stick length.
How to use this tool
- Measure each wall and add the lengths for the room perimeter.
- Total the width of doorways and openings that get no baseboard, and enter it.
- Set a waste factor (10% for a simple room, more for many corners).
- Enter the length of the trim boards you'll buy.
- Read the linear feet needed and the number of sticks to purchase.
Order the right amount of trim. Enter the room perimeter, subtract doorways, add a waste factor, and this tool tells you the linear feet and the number of sticks to buy.
Formula
Subtract door and opening widths from the perimeter, add a waste factor, then convert to whole sticks:
Net length = Perimeter − Door widths
Linear feet = Net length × (1 + Waste%)
Sticks = ⌈ Linear feet ÷ Stick length ⌉
How it works
Baseboard, casing, and crown trim are estimated in linear feet. We start with the room perimeter — the sum of all wall lengths — and subtract the width of doorways and other openings that get no baseboard. That net figure is the bare minimum of trim the room consumes if every cut were perfect and waste-free.
Real installations are not waste-free. Mitered inside and outside corners, scarf joints on long walls, and the occasional miscut all eat material, so we apply a waste factor — 10% for a simple rectangular room, more for rooms with many corners, bays, or short wall segments where off-cuts can't be reused. We then divide by the length of the trim boards you plan to buy and round up to whole sticks.
The estimate assumes a single height of trim run continuously around the walls. Buy a couple of extra feet if you are matching a stained or pre-finished profile that may be hard to re-order, and remember that longer sticks reduce the number of joints on long walls but are harder to transport and handle.
Worked example
40 ft perimeter, 6 ft of doorways, 10% waste, 16 ft sticks
- Net length = 40 − 6 = 34 ft.
- With 10% waste: 34 × 1.10 = 37.40 ft.
- Sticks = ⌈37.40 ÷ 16⌉ = ⌈2.34⌉ = 3 sticks.
Buy 3 sticks | 37.40 ft needed | Net 34.00 ft
Trim pieces by room size (square room, +10% waste, 16 ft sticks)
| Floor area | Perimeter | With waste | 16 ft sticks |
|---|---|---|---|
| 100 sq ft | 40.0 ft | 44.0 ft | 3 |
| 150 sq ft | 49.0 ft | 53.9 ft | 4 |
| 200 sq ft | 56.6 ft | 62.2 ft | 4 |
| 300 sq ft | 69.3 ft | 76.2 ft | 5 |
| 400 sq ft | 80.0 ft | 88.0 ft | 6 |
Key terms
- Linear feet
- A measure of length only (not area), used for trim, molding, and lumber sold by the running foot.
- Baseboard
- The trim board that runs along the bottom of interior walls, covering the wall-to-floor joint.
- Miter joint
- An angled cut, usually 45 degrees, that joins two pieces of trim at a corner. Miters create off-cut waste.
- Scarf joint
- An angled splice used to join two trim boards end-to-end along a long wall so the seam is less visible.
- Waste factor
- Extra material added to cover cutting losses and mistakes, typically 10% for trim work.
Frequently asked questions
- How much baseboard do I need?
- Add up the room perimeter, subtract the width of doorways, then add about 10% for waste. Divide by your board length and round up. A room with a 40 ft perimeter and 6 ft of doors needs roughly 37 ft, or three 16 ft sticks.
- How much waste should I add for trim?
- About 10% for a simple rectangular room. Rooms with many corners, bays, or short walls generate more off-cuts, so use 15% or more.
- What length of trim boards should I buy?
- Longer boards (12-16 ft) reduce visible joints on long walls but are harder to handle and transport. Match the stick length to your longest walls when possible.