How Much Paint for a 12x12 Room?

A 12×12 room is about as standard as it gets in American homes. Bedroom, home office, guest room — whatever you're painting, the math stays the same. Getting the paint estimate right on the first try means you skip that mid-project panic run to Home Depot.

Standard 12×12 Room Dimensions

Four walls at 12 feet each = 48 feet of perimeter. Standard 8-foot ceilings put you at 384 square feet of wall area (48 × 8). Got 9-foot ceilings? That's 432 square feet — common in newer construction.

Subtracting Doors and Windows

Most 12×12 rooms have one door and one or two windows. A standard interior door eats up about 21 square feet. A typical window runs around 15 square feet. After you subtract the openings:

• 1 door + 1 window: subtract 36 sq ft — paintable area roughly 348 sq ft
• 1 door + 2 windows: subtract 51 sq ft — paintable area roughly 333 sq ft

How Many Gallons for a 12×12 Room?

A gallon of decent paint covers about 350 square feet per coat. Do the math and this is what you're looking at:

• Walls only, 1 coat: 1 gallon
• Walls only, 2 coats (standard): 2 gallons
• Walls + ceiling, 2 coats: 3 gallons (2 for walls, 1 for ceiling)
• Dark-to-light switch: Add an extra gallon for a third coat

Ceiling and Trim Don't Paint Themselves

A 12×12 ceiling is 144 square feet — figure about 1 gallon for a single coat. Baseboards and door trim need roughly 1 quart of trim paint. Painting the closet interior too? Add another half gallon.

Paint Quality Changes the Math

Premium stuff like Benjamin Moore Aura pushes 400 sq ft per gallon. Budget brands might only hit 250–300. Spending an extra $10–15 per gallon on quality paint often means fewer coats — and less paint total. Cheap paint costs more in the long run.

Stuff That'll Save You a Headache

• Buy all your paint in one shot — different batches can have subtle color differences you'll notice on the wall.
• Save a quart for touch-ups. Label it with the room name and date so you're not guessing six months later.
• Run the numbers through a paint calculator before you head to the store — beats doing mental math in the aisle.
• Don't skip primer on new drywall or if you're going light over dark. You'll just end up doing a third coat of expensive paint instead.

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