How many gallons of paint for a 12x12 room?

1.93 gallons for two coats on the walls, so 2 one-gallon cans, with 8 ft ceilings; 2.2 (buy 3) at 9 ft and 2.48 (buy 3) at 10 ft. One coat of the same colour over sound paint is 0.96 gallons at 8 ft.

How much litre paint is needed for a 12x12 room?

About 6.3 litres for two coats on the walls (3.1 L for one), at the 10 m² per litre printed on many metric cans, with 8 ft ceilings and a door and two windows taken off. Check the coverage on your can and enter it in the paint calculator with the can size you can buy.

How much paint for a 12x12 room with 8 ft ceilings?

About 1.93 gallons for two coats on the walls (2 gallon cans), after deducting one door and two windows. One coat is 0.96 gallons.

How much paint for a 12x12 room with 9 or 10 ft ceilings?

Every extra foot of ceiling adds 48 sq ft of wall. At 9 ft the walls are 386 sq ft: 2.2 gallons for two coats, so 3. At 10 ft they are 434 sq ft: 2.48 gallons, still 3.

Usually yes. One coat is enough only when repainting the same colour on a sound surface. Changing colour, covering a dark wall or painting fresh plaster needs two coats, and a primer or mist coat on bare plaster on top of that.

Does this include the ceiling?

No, the first table is walls only. The 12 x 12 ft ceiling is 144 sq ft and takes about 0.82 gallons for two coats, so one gallon can of ceiling paint; the ceiling paint guide has the same figure and other ceiling sizes.

How many square feet does a gallon of paint cover?

Sherwin-Williams (2026) puts a gallon at about 350 to 400 sq ft per coat; this page, like every paint guide on the site, uses 350, the low end, so you are not short. Textured or porous walls take more, so use the figure on your can in the calculator.

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

You need 2 gallons of paint for a 12 x 12 ft room with 8 ft ceilings: its 338 sq ft of wall, after one door and two windows, takes 1.93 gallons for two coats at 350 sq ft per gallon, and 0.96 for one coat. In litres that is about 6.3 L for two coats at 10 m² per litre. With 9 ft ceilings buy 3 gallons and with 10 ft 3 gallons; the ceiling adds 0.82 gallons (1 can) for two coats. The tables have every case and the metric 4 x 4 m room.

Open the paint calculator

Paint for a 12 x 12 ft room

Wall area is the perimeter times the ceiling height: (12 + 12) x 2 = 48 ft of wall, times the height. The tables deduct one door (about 3 x 7 ft) and two windows (about 3 x 4 ft each). Change these in the paint calculator if your room is different; with the coverage set to 350 sq ft per gallon it gives the same figures as this table.

12 x 12 ft room, walls only, 1 door + 2 windows deducted, 350 sq ft per gallon
Ceiling	Wall area (sq ft)	1 coat (gal)	Cans (1 gal)	2 coats (gal)	Cans (1 gal)
8 ft	338	0.96	1	1.93	2
9 ft	386	1.1	2	2.2	3
10 ft	434	1.24	2	2.48	3

Walls and ceiling together

Painting the whole room in one go adds the 144 sq ft ceiling. Ceiling paint is usually a separate flat product, so the table gives it on its own and also the total if you use one paint for both. The ceiling paint guide has other ceiling sizes, quarts and textured ceilings.

12 x 12 ft room, two coats, 350 sq ft per gallon
Ceiling height	Walls (gal)	Ceiling (gal)	Same paint for both (gal)	Buy (1 gal cans)
8 ft	1.93	0.82	2.75	3
9 ft	2.2	0.82	3.03	4
10 ft	2.48	0.82	3.3	4

Reading the table

Cans are rounded up to whole gallons. If the exact figure is just over a whole number, a quart may be enough for the difference, but keep some for touch-ups from the same batch.
Trim, doors and radiators are painted with a different product and are not included. A door painted on both sides takes about 0.9 quarts for two coats.
Primer is separate. New drywall, bare plaster and patched areas need it before the colour coats.
Floor area is not what you paint: the square feet in a 12x12 room guide gives the floor, the walls and the volume side by side.

Metric: a 4 x 4 m room

The same room in metres is 4 x 4 m. Coverage of 10 m² per litre per coat is a common label figure for emulsion and the paint calculator's starting value; check your can.

4 x 4 m room, walls only, 2 coats, 1 door + 2 windows deducted, 10 m² per litre
Ceiling height	Wall area (m²)	Litres (2 coats)	5 L cans	2.5 L cans
2.4 m	34.1	6.8	2	3
2.7 m	38.9	7.8	2	4

Why coverage on the can is the number that matters

Two paints in the same aisle can differ a lot in coverage, and a rough or unsealed wall soaks up much more than a smooth one. Sherwin-Williams gives 350 to 400 sq ft per gallon as the usual range; the estimate is only as good as the coverage you put in, so read the can (it is usually given per coat) and, on porous surfaces, use the lower end of the range the manufacturer prints. The gallon coverage guide has the figures by surface, and the 10x10 room guide the smaller rooms.

Frequently asked questions

How much paint do I need for a 12x12 room?: 2 gallons for the walls with 8 ft ceilings and two coats: 338 sq ft of wall (384 sq ft less a door and two windows) x 2 coats / 350 = 1.93 gallons. Painting the ceiling too: 3 gallons in all if it is the same paint, or 2 of wall paint and 1 of ceiling paint.
How many gallons of paint for a 12x12 room?: 1.93 gallons for two coats on the walls, so 2 one-gallon cans, with 8 ft ceilings; 2.2 (buy 3) at 9 ft and 2.48 (buy 3) at 10 ft. One coat of the same colour over sound paint is 0.96 gallons at 8 ft.
How much litre paint is needed for a 12x12 room?: About 6.3 litres for two coats on the walls (3.1 L for one), at the 10 m² per litre printed on many metric cans, with 8 ft ceilings and a door and two windows taken off. Check the coverage on your can and enter it in the paint calculator with the can size you can buy.
How much paint for a 12x12 room with 8 ft ceilings?: About 1.93 gallons for two coats on the walls (2 gallon cans), after deducting one door and two windows. One coat is 0.96 gallons.
How much paint for a 12x12 room with 9 or 10 ft ceilings?: Every extra foot of ceiling adds 48 sq ft of wall. At 9 ft the walls are 386 sq ft: 2.2 gallons for two coats, so 3. At 10 ft they are 434 sq ft: 2.48 gallons, still 3.
Do I need two coats?: Usually yes. One coat is enough only when repainting the same colour on a sound surface. Changing colour, covering a dark wall or painting fresh plaster needs two coats, and a primer or mist coat on bare plaster on top of that.
Does this include the ceiling?: No, the first table is walls only. The 12 x 12 ft ceiling is 144 sq ft and takes about 0.82 gallons for two coats, so one gallon can of ceiling paint; the ceiling paint guide has the same figure and other ceiling sizes.
How many square feet does a gallon of paint cover?: Sherwin-Williams (2026) puts a gallon at about 350 to 400 sq ft per coat; this page, like every paint guide on the site, uses 350, the low end, so you are not short. Textured or porous walls take more, so use the figure on your can in the calculator.

How many square feet does a gallon of paint cover?
A gallon covers about 350 to 400 sq ft on smooth walls, less on rough or bare surfaces. Gallons for 400 to 2,000 sq ft at one and two coats, and litres per square metre.
How much paint do I need for a ceiling? Ceiling paint calculator for 10x10 to 20x20 ft
A 12x12 ceiling is 144 sq ft: 0.82 gallons for two coats at 350 sq ft per gallon, so 1 gallon or 4 quarts. 10x10 to 20x20, textured, and litres.
How much paint for a 10x10 room? (10x12, 12x14 and 14x16 too)
Gallons of paint for a 10x10 room with an 8 ft ceiling, a door and two windows, one or two coats, plus the ceiling; 10x12 to 14x16 rooms; 3x3 to 4x5 m rooms in litres.
How many square feet does a quart of paint cover?
A quart covers about 90 to 100 sq ft with one coat: what that means for a door, a wall, trim and a small ceiling at one and two coats, plus litres and 5 gallon pails.

Last updated 2026-10-13. Figures are planning estimates from typical product data: check the yield, size or coverage printed on what you buy and round up.