How many square feet is a 12x12 room? (and other common sizes)
A 12 x 12 ft room is 144 square feet of floor (13.4 square metres), with 48 ft of wall around it. With an 8 ft ceiling the walls add up to 384 square feet before openings, the room holds 1,152 cubic feet of air, and painting the walls takes about 1.9 gallons for two coats. The table gives the same figures for the other common room sizes.
Common room sizes: floor, walls and volume
Floor area is length x width. Wall area is the perimeter times the ceiling height, here 8 ft; the net figure takes off one door (about 3 x 7 ft) and two windows (about 4 x 3 ft), which is what you paint. Volume is floor area x height. The 3D room planner draws any shape, including L-shaped rooms, and gives the same surfaces with your own doors and windows.
| Room | Floor (sq ft) | Floor (m²) | Perimeter (ft) | Walls gross (sq ft) | Walls net (sq ft) | Volume (cu ft) |
|---|---|---|---|---|---|---|
| 10 x 10 ft | 100 | 9.3 | 40 | 320 | 273.82 | 800 |
| 10 x 12 ft | 120 | 11.1 | 44 | 352 | 305.82 | 960 |
| 11 x 11 ft | 121 | 11.2 | 44 | 352 | 305.82 | 968 |
| 12 x 12 ft | 144 | 13.4 | 48 | 384 | 337.82 | 1,152 |
| 12 x 14 ft | 168 | 15.6 | 52 | 416 | 369.82 | 1,344 |
| 12 x 15 ft | 180 | 16.7 | 54 | 432 | 385.82 | 1,440 |
| 14 x 16 ft | 224 | 20.8 | 60 | 480 | 433.82 | 1,792 |
| 15 x 20 ft | 300 | 27.9 | 70 | 560 | 513.82 | 2,400 |
| 16 x 20 ft | 320 | 29.7 | 72 | 576 | 529.82 | 2,560 |
A 12x12 room with 8, 9 and 10 ft ceilings
The floor does not change with the ceiling, but everything on the walls does: a 10 ft ceiling adds a quarter to the wall area, the paint and the heating volume.
| Ceiling | Walls gross (sq ft) | Walls net (sq ft) | Volume (cu ft) | Paint, two coats (gal) | Buy (gallons) |
|---|---|---|---|---|---|
| 8 ft | 384 | 337.82 | 1,152 | 1.9 | 2 |
| 9 ft | 432 | 385.82 | 1,296 | 2.2 | 3 |
| 10 ft | 480 | 433.82 | 1,440 | 2.5 | 3 |
What to order for each room
Flooring is the floor area plus 10% for cuts; paint is the net wall area divided by the coverage on the can, times two coats. Both columns come from the same room dimensions, so measuring once is enough.
| Room | Flooring to order (sq ft) | Wall paint (gal) | Buy (gallons) |
|---|---|---|---|
| 10 x 10 ft | 110 | 1.6 | 2 |
| 10 x 12 ft | 132 | 1.7 | 2 |
| 11 x 11 ft | 134 | 1.7 | 2 |
| 12 x 12 ft | 159 | 1.9 | 2 |
| 12 x 14 ft | 185 | 2.1 | 3 |
| 12 x 15 ft | 198 | 2.2 | 3 |
| 14 x 16 ft | 247 | 2.5 | 3 |
| 15 x 20 ft | 330 | 2.9 | 3 |
| 16 x 20 ft | 352 | 3 | 4 |
How the numbers are worked out
Square feet: 12 x 12 = 144. Square metres: multiply square feet by 0.0929, or measure in metres (3.66 x 3.66 m) and multiply. Perimeter: 2 x (12 + 12) = 48 ft. Walls: 48 x 8 = 384 square feet. Volume: 144 x 8 = 1,152 cubic feet. Measure at floor level from wall to wall, not skirting to skirting, and for an irregular room split it into rectangles.
Before you buy
- Painting: the 12x12 room paint guide has the full worked example and the ceiling guide covers the fifth surface.
- Tiling the floor: the 12x12 tile guide turns square feet into tiles and boxes.
- Several rooms at once: draw them in the room planner and it totals floor, ceiling, walls and skirting for the whole floor.
Frequently asked questions
- How many square feet is a 12x12 room?
- 144 square feet: 12 multiplied by 12. That is 13.38 square metres, or 16 square yards, the unit carpet is sometimes priced in. Order about 159 square feet of flooring to allow 10% for cuts.
- How many square feet of wall are in a 12x12 room?
- 384 square feet with an 8 ft ceiling: the perimeter (48 ft) times the height. Take off about 46.18 square feet for a door and two windows and you have 337.82 square feet to paint or paper. A 9 ft ceiling makes it 432 square feet gross.
- How many cubic feet is a 12x12 room?
- 1,152 cubic feet with an 8 ft ceiling (144 x 8), 1,296 with 9 ft and 1,440 with 10 ft. Cubic feet is what heater, air conditioner and dehumidifier sizing charts ask for.
- How much paint do I need for a 12x12 room?
- About 1.9 gallons for two coats on the walls at 350 square feet per gallon, after a door and two windows: buy 2. The ceiling is another 0.4 gallons per coat. The 12x12 room paint guide has 8, 9 and 10 ft ceilings and the metric version.
- How much flooring do I need for a 12x12 room?
- 159 square feet including 10% waste. Boxes of laminate or vinyl plank are labelled in square feet, so divide by the box coverage and round up; a 20 square feet box means 8 boxes. For 12 x 12 tiles see the tile guide.
- Is a 12x12 room big?
- It is an average bedroom in most new houses and a small living room. It fits a queen bed with two nightstands and a dresser, or a sofa, two chairs and a coffee table. Furniture is placed against walls, so the wall length matters as much as the area: 48 ft in a 12 x 12, only 44 ft in a 10 x 12 room with almost the same area.
More guides
- How much does a cinder block garage cost? (blocks, mortar, grout and slab for 1, 2 and 3 car)
Blocks, mortar and grout for 1 to 3 car block garages, 12x20 to 36x24 ft, 8 ft walls, doors and windows taken off, plus the 4 in slab, at 2026 prices.
- How much does a ton of gravel cover? (at 2, 3 and 4 inches, by stone)
A ton of 3/4 in crushed stone is 0.79 cubic yards: about 85 sq ft at 3 in, 128 at 2 in, 64 at 4 in. Coverage by stone, tons for 100 to 1,000 sq ft, price.
- How many 73 mm bricks per square metre? (Scottish and imperial bricks)
About 54 per m² for a 215 x 102.5 x 73 mm Scottish brick, 51 for a 228 x 108 x 73 mm imperial one at 10 mm joints, against 59 for 65 mm; joints, 10-100 m².
- How many concrete blocks do I need for a wall?
8x8x16 blocks per square foot and for walls from 10x4 to 40x8 ft with 5% waste, mortar volume, and the metric 440 x 215 mm block per square metre.
Last updated 2026-09-12. Figures are planning estimates from typical product data: check the yield, size or coverage printed on what you buy and round up.