Paint Coverage Calculator
Paint coverage is printed on the can, not in a rule of thumb. Enter the coverage rate from your actual product and this calculator tells you how many gallons to buy — and how much the same room works out in litres.
Results
Enter your measurements above and press Calculate.
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Questions people ask
How much paint do I need for a room?
Multiply wall and ceiling area by coats, subtract the door and window area, then divide by the coverage rate on the can. A 12 × 8 room with an 8 foot ceiling, one door, two windows and two coats needs about 3 gallons at 350 sq ft per gallon.
What is a good coverage rate for paint?
Most quality latex paint covers 350 to 400 square feet per gallon on the first coat and more on the second. Oil-based and cheap paint typically cover less. The label number is authoritative.
Do I really need two coats?
On new drywall or bare wood, always. Over existing paint in the same color, one coat of good quality paint with enough sheen often suffices. Fresh primer is needed when going from dark to light or changing sheen.
Why does the can say one gallon but I should buy more?
The label rate assumes a properly prepared surface and normal application. Rough surfaces, cold weather, and heavy roller nap all reduce the real coverage. Buy one extra can for a full room rather than running short mid-project.
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