How much paint do I need for a 12x12 room?

About 2 gallons for walls with two coats, plus a gallon of primer on new drywall. The calculator figures it from your dimensions.

How many square feet does a gallon of paint cover?

Roughly 350 sq ft per gallon per coat on smooth walls — less on textured or porous surfaces.

Walls alone, or the ceiling too — pick one.

Walls only Ceiling stays as-is Walls + ceiling The whole room, top to bottom

Measure wall to wall, floor to ceiling.

Length (ft)

Width (ft)

Ceiling height (ft)

Doors

Windows

We subtract ~21 ft² per door and ~15 ft² per window so you don't overbuy.

Two thin coats always beat one thick one.

1 coat Touch-ups or same-color refresh 2 coats The pro standard — even color, better coverage

Add primer New drywall, patched spots, or a big color change — one coat

Buy this many gallons

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💡 Pro field tips

🧰 Tools you'll need

Tap to check off as you load up.

Est. project cost (optional)

Price per gallon ($)

Labor hours

Labor rate ($/hr)

Save to job log (optional)

File this estimate under a job name or PO to track what to order. Leave blank to file under "General".