How much paint for a 12x12 room?
Paint is ordered by wall area, not floor area. For a 12 × 12 ft room with 8 ft walls the perimeter is 48 ft, so gross wall area is 384 sq ft. This example deducts 30 sq ft for a door and a window, leaving 354 sq ft. Formula: wall area × coats ÷ coverage per gallon, rounded up to whole gallons.
| Coats | Coverage (planning assumption) | Gallons before rounding | Gallons to buy |
|---|---|---|---|
| 2 | 350 sq ft per gallon | 2.02 | 3 |
| 3 | 350 sq ft per gallon | 3.03 | 4 |
3 gallons is the rounded-up figure for 2 coats (2.02 gallons before rounding). Measure the actual openings and use the coverage printed on your paint can, then change the inputs in the planner. Ceiling paint, primer and trim paint are not included.
Assumptions and sources
Waste percentages (5, 10, 15 and 20 percent), 350 sq ft per gallon paint coverage, 2 coats and a 1/8 in grout joint are RoomTakeoff planning assumptions, not figures taken from a manufacturer or standards document. Check the label on your tile, paint and trim, and confirm installation practice with the tile manufacturer or the Tile Council of North America resources linked below.
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