How much paint do I need?
Enter your room size and we’ll tell you how many cans to buy, with doors and windows taken out.
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How this is calculated
We multiply the perimeter of the room by the wall height, then subtract about 21 sq ft for each door and 15 sq ft for each window (1.9 m² and 1.4 m² in metric).
One gallon of interior paint covers roughly 350 sq ft per coat, or about 10 m² per litre. We round up so you never run out halfway through a wall.
Do I really need two coats?
Usually yes. A second coat gives even color and hides roller marks. One coat can work if you’re repainting the same color with a paint-and-primer product.
Should I buy extra?
Keeping a small amount for touch-ups is smart. Rounding up to the next full can usually leaves enough.