Paint Calculator
Estimate how many gallons of paint you need based on room dimensions, number of doors and windows, and number of coats.
ft
ft
ft
sq ft
Number of Coats
Gallons Needed
1.98
Buy: 2 gallons
Paint Estimate
- Total Wall Area
- 396 sq ft
- Deductions (doors + windows)
- 50 sq ft
- Paintable Area
- 346 sq ft
- Gallons (2 coats)
- 1.98 gal
- Suggested Purchase
- 2 gallons
Coverage estimate assumes smooth surfaces at 350 sq ft/gallon. Rough, textured, or porous surfaces may require more. Add 10–15% extra for touch-ups and waste.
Paint Coverage Formula
Paintable area = total wall area − (doors × 21 sq ft) − (windows × 15 sq ft). Gallons needed = (paintable area × coats) ÷ 350. Round up to the nearest quart or gallon.
Frequently Asked Questions
- One gallon of paint typically covers 350–400 square feet per coat on smooth surfaces. Textured or porous surfaces may require more.
- Most painting projects require two coats for full, even coverage — especially when painting over a darker color or applying a light color.
- Yes. Buy 10–15% more than estimated to account for touch-ups, uneven surfaces, and potential returns if you need more later (color matching is easier with the same batch).