Paint Calculator
Estimate how many gallons of paint you need for any room or project.
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ft
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Paint Needed
2 gallons
for 2 coats
How to Calculate Paint Needed
Wall Area = 2 × (Length × Height) + 2 × (Width × Height)
Paintable = Wall Area − (Doors × 20) − (Windows × 15)
Gallons = (Paintable × Coats) ÷ 350
Paintable = Wall Area − (Doors × 20) − (Windows × 15)
Gallons = (Paintable × Coats) ÷ 350
Paint Coverage Guide
| Paint Type | Coverage per Gallon |
|---|---|
| Interior wall paint | 350–400 sq ft |
| Primer | 300 sq ft |
| Exterior paint | 250–300 sq ft |
| Ceiling paint | 350–400 sq ft |
Frequently Asked Questions
How much paint do I need for a room?
Measure the wall area (length × height of each wall), subtract doors and windows, then divide by 350–400 sq ft per gallon. A typical 12×12 room with 8ft ceilings needs about 2 gallons for two coats.
How many square feet does a gallon of paint cover?
One gallon covers approximately 350–400 square feet with one coat. For two coats, plan on 175–200 sq ft per gallon. Primer covers about 300 sq ft per gallon.
How many coats of paint do I need?
Typically two coats for good coverage, especially when changing colors. One coat may suffice when repainting with the same color. Dark colors over light may need three coats.
Should I subtract doors and windows?
Yes. A standard door is about 20 sq ft and a window about 15 sq ft. This calculator subtracts them automatically to avoid over-ordering.