How much paint for a 12x15 room?
396 sq ft of wall and 2.26 gallons for two coats make a 12x15 the largest room on this chart that still finishes without a third full gallon.
A 12x15 ft room with 8-foot ceilings needs 2.26 gallons of paint for two coats — buy 2 × 1-gallon cans + 2 × quarts. That is 432 sq ft of gross wall, 396 sq ft after deducting one door (21 sq ft) and one window (15 sq ft), covered twice against 350 sq ft per gallon. With the standard 10% waste buffer it comes to 2.49 gallons, about $112 of paint. Having it painted runs about $553 for the walls, or $1,007 with the ceiling and trim.
Rates and coverage figures updated August 2026. Compiled 2026 from sources last updated 2023–2026.What to actually buy
- 2 × 1-gallon cans + 2 × quarts of wall color — $112, leaving 0.01 gal spare.
- On the walls, rounding up to 3 full gallons instead costs $120 and leaves 0.51 gal you will not use.
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What a 12x15 room is, and what that means for the job
By the time houses were going up in the 1990s the primary bedroom had settled at about 12 by 15, and in an older house the same 180 sq ft is usually the dining room. Furnished, it holds a queen bed, two nightstands and a dresser: none of it heavy enough to justify help, all of it in the way. Everything goes to the center, and the 54 ft of baseboard around the edge gets taped in a single pass.
The closet is a reach-in with bifold doors on one of the 12 ft walls. Take the doors off the track before you start, because painting around bifolds is how you end up with a stripe of old color at the jamb. Whether you paint the closet interior is a separate decision, and it adds wall the numbers above do not include. A primary bedroom gets repainted about once a decade, so most people roll the ceiling the same weekend: 180 sq ft is just over a gallon for two coats, so buy a gallon and a quart of ceiling paint.
The numbers behind the answer
| Ceiling height | Gross wall | Net wall | 1 coat | 2 coats | 2 coats + waste |
|---|---|---|---|---|---|
| 8 ft | 432 | 396 | 1.13 | 2.26 | 2.49 |
| 9 ft | 486 | 450 | 1.29 | 2.57 | 2.83 |
| 10 ft | 540 | 504 | 1.44 | 2.88 | 3.17 |
The arithmetic is worth seeing once: 432 sq ft of gross wall comes from 2 × (12 + 15) × 8 ft. Take off 21 sq ft for the door and 15 for the window and you have 396 sq ft to cover. Two coats is 792 sq ft of coverage, and at 350 sq ft per gallon that is 2.26 gallons. Every figure on this page comes from that one calculation.
No other common room size shares a 54-foot perimeter, so the 12x15 sits on its own in the chart. What it does share is the rule underneath it: wall paint tracks the distance around the room, not the area of the floor. That is why a 12x15 at 180 sq ft of floor needs 2.26 gallons while a room with more floor and a tighter perimeter can need less.
What to buy
Buy it as two gallons plus two quarts, $112. With waste you need 2.49 gallons and that combination is exactly 2.50, which is the whole reason to buy it this way: the third full gallon costs $8 more and leaves you half a gallon of a color you will never use again. Two flat gallons is the real mistake. That is half a gallon short, and you find out in the middle of the second coat with the room already empty and taped.
Painting the ceiling and trim too
| Surface | Area | Paint, 2 coats | Buy |
|---|---|---|---|
| Walls | 396 sq ft net | 2.49 gal | 2 × 1-gallon cans + 2 × quarts |
| Ceiling | 180 sq ft | 1.13 gal | 1 × 1-gallon can + 1 × quart |
| Trim and baseboard | 51 linear ft | 0.22 gal | 1 × quart |
What changes the answer
One hundredth of a gallon separates what this room needs, 2.49 with waste, from the 2.50 you carry home, so it flips easily. A 9 ft ceiling runs an extra foot around 54 ft and asks 2.57 gallons: three cans. Orange peel takes 2.26 to 2.43, or 2.67 with waste, also three cans. A third coat over an old dark red is 3.39 before waste. Only one common change goes your way, since the basis counts a single window and a bedroom with two subtracts 15 sq ft and 0.09 gallon.
| Change | Paint needed | Effect |
|---|---|---|
| Baseline | 2.26 gal | the figure this page answers with |
| 9 ft ceiling | 2.57 gal | +0.31 gal |
| 10 ft ceiling | 2.88 gal | +0.62 gal |
| Orange-peel texture | 2.44 gal | +0.17 gal |
| Knockdown texture | 2.88 gal | +0.62 gal |
| Three coats | 3.39 gal | +1.13 gal |
| A second window | 2.18 gal | −0.09 gal — an opening removes wall you would have had to cover |
| No window at all | 2.35 gal | +0.09 gal |
Doing it yourself against hiring it out
| Route | What you pay | What it takes |
|---|---|---|
| Do it yourself | $112 of paint, plus roughly $22 of sundries | 2 × 1-gallon cans + 2 × quarts, one weekend |
| Hire it out | $553 for walls only | about 7.2 painter-hours |
| Hire it out, full room | $1,007 with ceiling and trim | walls, ceiling and 51 ft of trim |
A single room can also fall under a painter's job minimum, which runs $250–$500 whatever the square footage covers — mobilizing a crew costs the same for one room as for five. If you are pricing work rather than buying paint, the painting estimate calculator builds the full line-itemed bid.
A 12x15 room, answered
How much paint for a 12x15 room?
2.26 gallons covers two coats, and the buy is two gallons plus two quarts. Around the room is 54 ft; times an 8 ft ceiling is 432 sq ft, and deducting 21 sq ft of door and 15 sq ft of window leaves 396 sq ft of wall. Two coats is 792 sq ft of coverage, divided by 350 sq ft per gallon. Padded 10% for waste, the requirement is 2.49 gallons and the two quarts bring you to 2.50.
Will two gallons and one quart cover a 12x15 room?
No. That is 2.25 gallons against a padded 2.49, so you are a quarter gallon short, which is most of one wall's second coat. The second quart costs about $16 and puts you on 2.50, a hundredth over the line. If the walls carry any texture at all, or the new color is going over something much darker, skip the quarts entirely and take a third full gallon. Check your own numbers here.
Why does a 12x15 room need less paint than a 12x16?
One extra foot of length is 16 sq ft of wall. Going from 12x15 to 12x16 adds 2 ft of perimeter, a foot on each of two walls, and 2 ft times an 8 ft ceiling is 16 sq ft, which is how 396 sq ft becomes 412. That is a small difference, but it falls on the wrong side of a can: the 12x15 finishes on two gallons and two quarts while the 12x16 needs three full gallons.
How much does it cost to paint a 12x15 bedroom?
About $112 in materials, two gallons at $40 plus two quarts at roughly $16 each. A pro repainting the same 396 sq ft of wall comes in near $553, inside the $1.00 to $3.00 per sq ft band for interior repaint work and clear of the $250 to $500 minimum most crews carry. Adding the ceiling raises both figures, and ceiling paint is bought separately from your wall color.
Sources and method
Coverage rates come from Sherwin-Williams and Benjamin Moore product data sheets; cost ranges were compiled in August 2026 from HomeGuide and Angi/HomeAdvisor, whose own pages date from 2023 to 2026. Angi owns HomeAdvisor, so those are one source and not two. Quantities on this page assume 350 sq ft per gallon per coat on smooth primed drywall, a 21 sq ft door and a 15 sq ft window; sources put windows anywhere from 10 to 16 sq ft, so change the opening counts in the calculator if yours differ. The full constants are on the paint coverage chart, and the cost basis is set out on interior painting cost per square foot.
This is an estimate for planning, not a quote. Measure your own room before buying.