How Much Paint Do I Need for a 12x12 Room?
The quick answer
1.9 gallons
For a 12x12 room with 8 ft walls, one door and two windows, you'll need about 1.9 gallons of paint for two coats. That covers 334 sq ft of wall, so buy 2 gallon cans.
📏 Your room is different? Adjust the numbers below.
Your room
You'll need about
1.9 gallons
334 sq ft of wall · buy 2 cans to be safe
Buy one extra can if your walls are new, textured or a much darker colour — thirsty walls drink more paint!
How it changes
| Scenario | Result | Details |
|---|---|---|
| 8 ft walls, 2 coats | 1.9 gallons | 334 sq ft of wall · buy 2 cans to be safe |
| 9 ft walls, 2 coats | 2.2 gallons | 382 sq ft of wall · buy 3 cans to be safe |
| 10 ft walls, 2 coats | 2.5 gallons | 430 sq ft of wall · buy 3 cans to be safe |
| 8 ft walls, 1 coat | 1.0 gallons | 334 sq ft of wall · buy 1 can to be safe |
Why a 12x12 room needs less paint than you think
A 12x12 room has four walls that each measure 12 feet wide. With 8 ft ceilings that's 384 square feet of wall before you take anything out. A standard door removes about 20 sq ft and each window about 15 sq ft, which brings the paintable area down to roughly 334 sq ft.
One gallon of good interior paint covers around 350 sq ft per coat on smooth, primed drywall. Two coats means you're really painting about 670 sq ft, which is just under two gallons.
When to buy extra
- Big colour change: going from dark red to soft white can need a third coat. Use a tinted primer first and you'll often get away with two.
- Textured or new drywall: thirsty surfaces soak up more paint. Add 10–15%.
- Touch-ups later: keep a small leftover amount, labelled with the room name, for scuffs.
Ceiling and trim are separate
This estimate is for walls only. A 12x12 ceiling is 144 sq ft, so a single gallon of ceiling paint usually covers two coats. Trim and doors normally take about a quart of semi-gloss.
Quick shopping list
Walls, a gallon of primer if you're covering a dark colour, a 9-inch roller with a 3/8-inch nap, an angled brush for cutting in, and painter's tape.
Questions people ask
One gallon covers about 350 sq ft per coat, so it's enough for a single coat on 8 ft walls. Most rooms need two coats, so plan on two gallons.
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Last updated September 28, 2026. These results are friendly estimates to help you plan — always double-check before buying or making big decisions.