The Trim & Door Paint Calculator works out how much paint you need for woodwork: doors (both sides), window trim, baseboards, crown molding and cabinets. Results are in quarts and gallons, since trim paint is often bought by the quart.
Trim & Door Paint Calculator
Paint for doors, baseboards, window and door trim, crown moulding and cabinets — in quarts or gallons.
It uses allowances of 40 ft² per door (both sides including edges) and 12 ft² per window’s trim, plus baseboard and crown length × face height and any cabinet surface area you enter.
Formula
Area = 40 × doors + 12 × windows + baseboard length × height + crown length × height + cabinets
Paint = area × coats ÷ coverage
Heights are converted from inches to feet (÷ 12).
How the Calculation Works
Step 1: Add up the surface of each trim element.
Step 2: Multiply by coats.
Step 3: Divide by coverage and convert to quarts (1 gal = 4 qt).
Example Calculation
Given: 4 doors, 4 windows with trim, 120 ft of 4 in baseboard, 2 coats, 350 ft²/gal
- Doors = 4 × 40 = 160 ft²
- Windows = 4 × 12 = 48 ft²
- Baseboard = 120 × 0.333 = 40 ft²
- Total = 248 ft² → 248 × 2 ÷ 350 ≈ 1.42 gal ≈ 5.7 qt
Buy 1 gallon + 2 quarts, or 2 gallons.
Variables Explained
| Input | Meaning |
|---|---|
| Doors | Each counts as 40 ft² — both faces and edges of a typical interior door |
| Windows with trim | 12 ft² of casing and sill per window |
| Baseboard / crown | Length × visible face height |
| Cabinet surface area | Door and frame faces you will paint |
Material Estimation Notes
- Paneled doors and detailed moldings have more surface than flat ones.
- Trim and cabinets often need primer, especially over stained wood or glossy finishes.
- Coverage for enamels may differ from wall paint; check the can.
Frequently Asked Questions
How much paint do I need for trim?
Add doors, window trim and baseboard areas, multiply by coats and divide by coverage.
How much paint to paint a door?
At 40 ft² for both sides, two coats at 350 ft²/gal: about 0.23 gal, just under a quart.
How much paint for baseboards?
Length × face height; 100 ft of 4 in baseboard is about 33 ft².
How much paint for kitchen cabinets?
Measure the faces you’ll paint (doors on both sides, frames) and enter the area.
Should I buy quarts or gallons?
Compare prices: when you need three or more quarts, a gallon can is often the better buy.