Paint calculator
How much paint do you need?
Enter the area you're painting and the number of coats to get gallons needed, gallons to buy, and an estimated cost.
Enter your area
We assume 350 sq ft of coverage per gallon (a typical mid-grade interior/exterior paint) — check your can's label and adjust if it differs.
Results
- Area to paint
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- Paint needed
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- Gallons to buy
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- Estimated cost
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Rounded up to whole gallons — paint stores don't sell partial cans.
Estimates only — check your paint's actual coverage rate on the can before buying.
How it's calculated
Area × coats ÷ coverage rate.
We multiply your area by the number of coats, then divide by the coverage rate (350 sq ft per gallon by default) to get exact gallons needed — then round up to whole gallons, since paint stores don't sell partial cans.
FAQ
Common questions
How much area does a gallon of paint cover?
Most mid-grade interior and exterior paints cover around 350 sq ft per gallon on a single coat over a primed, smooth surface. Textured surfaces, unprimed drywall and darker color changes all reduce coverage — check your specific can's label.
How many coats do I need?
Two coats is standard for most color changes and gives the most even, durable finish. One coat can work for a touch-up in the same color; going from a dark wall to a light color may need three.
Do I need primer too?
Primer isn't included in this estimate. Budget for it separately if you're painting bare drywall, covering a stain, or making a big color change (dark to light) — primer typically covers about the same area per gallon as paint.
Already know your square footage — what should I do differently for a room?
This calculator takes a flat area directly. If you'd rather enter a room's dimensions and have us subtract doors and windows automatically, use the room paint calculator instead.