How much paint for trim, baseboards and doors?
Trim needs far less paint than walls. Multiply each run's linear feet by its face width for square feet, add both faces of each door, then divide by the paint's spread rate. A 12 × 14 ft bedroom's baseboard, casing and one door total about 63 sq ft, so two coats take 2 quarts of trim enamel.
Updated · By the Interior Redesign AI editorial team · Sources cited on the page
Assumption: default face widths and a 30 × 80 in slab door are typical sizes, not your trim. Measure yours for a closer number.
Trim paint to buy
2 quarts
0.31 gallons exactly, rounded up to cans.
| Baseboard | 16.3 sq ft |
|---|---|
| Casing | 12.9 sq ft |
| Crown | 0 sq ft |
| Doors, both faces | 33.3 sq ft |
| Total × 2 coats | 125.2 sq ft |
At 400 sq ft per gallon. Benjamin Moore lists 400-500 sq ft per gallon for Advance Satin; panel doors and deep profiles take a bit more, so round up.
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Key numbers
- Trim enamel spread rate
- 400-500 sq ft per gallon (Benjamin Moore Advance Satin data sheet); we use 400
- Area of a trim run
- linear feet × face width in inches ÷ 12
- One 30 × 80 in door
- 16.7 sq ft per face, 33.3 sq ft both faces
- A quart
- 1/4 gallon, about 100-125 sq ft at the 400-500 rate
- Coats
- 2 for a color change or bare primed wood; 1 can do for a same-color refresh
Worked example
A 12 × 14 ft bedroom with one door and two windows
Baseboard around the room minus a 3 ft doorway, casing on both sides of the door opening and around two 36 × 48 in windows, one 30 × 80 in door painted on both faces, two coats.
- Baseboard: 2 × (12 + 14) − 3 = 49 ft × 4 in ÷ 12 = 16.3 sq ft.
- Casing: 32.5 ft at the door + 29.7 ft at the windows = 62.2 ft × 2.5 in ÷ 12 = 13 sq ft.
- Door: 30 × 80 in × 2 faces ÷ 144 = 33.3 sq ft.
- Total 62.6 sq ft × 2 coats ÷ 400 = 0.31 gallons.
Buy 2 quarts of trim enamel for this room.
How we calculate
Each trim run is a strip: its paintable area is the linear feet times the face width. We add baseboard, door and window casing and crown, then both faces of each door slab (width × height × 2), multiply by coats and divide by the spread rate.
The default spread rate is 400 sq ft per gallon, the low end of the 400-500 sq ft Benjamin Moore publishes for Advance Satin, a waterborne alkyd it recommends for trim and doors. Your can's data sheet may differ; enter its number.
Assumptions, all editable: face widths of 4 in for baseboard, 2.5 in for casing and 4 in for crown, and a 30 × 80 in flat slab door. Panel doors, deep profiles and door edges take a little more, so round up rather than down. We round the result up to whole quarts, and three or more quarts up to a gallon, because a gallon usually costs less than three quarts (a shelf-price assumption).
Estimates, sources
Planning estimates and published guidelines, not quotes, designs or code rulings. Figures were checked on each source on the date shown. Local prices, your home and your jurisdiction's adopted code decide the real answer.
- Advance Waterborne Alkyd Interior/Exterior, Satin W792: technical data sheet (W792 US 090826) (Benjamin Moore, as of Oct 26, 2026): spread rate per gallon 400-500 sq ft; recommended for primed and previously painted cabinets, trim, doors, walls, ceilings and furniture
- Paint Calculator (Housecall Pro, 2025): doors about 21 sq ft, windows about 15 sq ft each
Trim paint for a room vs a whole house
For a whole house the numbers grow but stay modest: 400 ft of baseboard, 500 ft of casing, 120 ft of crown and 12 doors come to about 678 sq ft, or 3 gallons + 2 quarts for two coats at 400 sq ft per gallon.
| Job | Paintable area | Buy |
|---|---|---|
| One door, both faces | 33 sq ft | 1 quart |
| 50 ft of baseboard | 17 sq ft | 1 quart |
| Bedroom (example above) | 63 sq ft | 2 quarts |
| Whole house (above) | 678 sq ft | 3 gallons + 2 quarts |
Which paint for trim and doors
Trim and doors take knocks and hand oils, so most painters use a harder, more washable enamel in satin or semi-gloss rather than the wall paint. Waterborne alkyds and urethane-modified enamels level out brush marks and cure hard. Prime bare wood and patched spots first, and sand glossy old oil paint before a waterborne coat, as the Advance data sheet advises.
How to use this tool
Measure the runs
Linear feet of baseboard, door and window casing, and crown. Skip what you are not painting.
Check the face widths
Measure the visible face of each trim profile in inches; the defaults are typical sizes.
Count the doors
Doors to paint, their size and whether you paint both faces.
Set coats and spread rate
Two coats is the default; enter the spread rate from your can's data sheet if it differs.
Questions
How much paint do I need for baseboards?
Very little: 100 ft of 4 in baseboard is about 33 sq ft, so two coats take about 0.17 gallons at 400 sq ft per gallon. One quart covers it.
How much paint does it take to paint a door?
A 30 × 80 in door is about 16.7 sq ft per face. Both faces, two coats, is about 67 sq ft, or roughly a sixth of a gallon. A quart paints about one to two doors, both sides, two coats.
Should I buy quarts or a gallon of trim paint?
Quarts for a room or two; a gallon once the job passes about three quarts, since a gallon usually costs less than three quarts. Keep a little for touch-ups.
How many coats does trim need?
Two coats for a color change or newly primed wood. A single coat can refresh trim in the same color in good condition.
What sheen is best for trim?
Satin or semi-gloss is the usual choice: tougher and easier to wipe than flat or eggshell wall paint. High gloss shows every dent and brush mark.
Do I paint the door edges?
Usually yes, but they add little area. The calculator counts the two faces only; rounding up to the next quart covers the edges.
Numbers done. Now see it.
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