How Much Paint for a 10x12 Room?
The short answer: 2 gallons for two coats. There is no cheaper combination that works.
A 10x12 room with 8-foot ceilings needs 2 gallons of paint for two coats. The exact requirement is 1.72 gallons, and there is no cheaper way to buy it. A gallon plus a quart is only 1.25 gallons — 437 square feet of coverage against the 602 that two coats requires.
Estimates only. Textured walls, high ceilings, sprayers and major colour changes can all increase the amount you need. Always buy slightly more than the calculation suggests.
Paint needed for a 10x12 room
| Room / surface | Surface | Coats | Paint | Paint cost |
|---|---|---|---|---|
| Walls only, 1 door, 2 windows | 301 sq ft | 2 | 2 gal | $70 |
| Walls only, 1 coat | 301 sq ft | 1 | 1 gal | $35 |
| Walls only, 3 coats | 301 sq ft | 3 | 3 gal | $105 |
| Walls and ceiling, 2 coats | 421 sq ft | 2 | 3 gal | $105 |
| Walls only, 9-foot ceilings | 345 sq ft | 2 | 2 gal | $70 |
Two coats at 350 sq ft per gallon, one door and two windows unless stated otherwise.
Where the 2 gallons comes from
A 10x12 room has a perimeter of 44 feet. At 8-foot ceilings that is 352 square feet of wall. Subtract one door and two windows — 51 square feet — and you are painting 301 square feet.
Two coats is 602 square feet. At 350 square feet per gallon that is 1.72 gallons, which rounds up to 2 gallons.
Worth knowing before you reach the till: there is no cheaper combination that works. A gallon plus a quart is 1.25 gallons — 437 square feet of coverage against the 602 you need. The 2 gallons is not an upsell, it is the minimum purchase.
The number that actually matters: the perimeter
Paint follows the perimeter, not the floor area. A 10x12 room and an 8x15 room both have a floor area of 120 square feet — but perimeters of 44 and 46 feet. The 8x15 room needs slightly more paint.
This is why estimating from floor area alone goes wrong in long, narrow rooms. Always measure the walls.
What it costs
At $35 per gallon, expect about $70 for the walls, roughly $49 for primer if you need 2 gallons, and about $30 for rollers, brushes, tape and drop cloths. A realistic budget for painting a 10x12 room yourself is $100 to $150.
Frequently asked questions
Is 1 gallon enough for a 10x12 room?
For one coat, yes — 1 gallon covers 350 square feet against the 301 square feet of wall. For the standard two coats you need 2 gallons.
How much paint for a 10x12 room with the ceiling?
3 gallons. The walls need 2 and the 120 sq ft ceiling adds roughly one more, or a separate gallon of flat ceiling paint.
How many square feet is a 10x12 room?
The floor is 120 square feet. The paintable wall area, after subtracting a door and two windows, is about 301 square feet.