🎨 Home Improvement & DIY Painting
Paint Coverage & Gallon Calculator
Estimate the exact number of paint cans (gallons or liters) required for your room, accounting for perimeter walls, ceiling, doors, windows, and multiple coats.
Room Dimensions (Feet)
Deductions & Options
Estimated Paint Required
3 Gallons
Net Wall Area
432 sq ft
40.1 m²
Total Paint Area
864 sq ft
2 Coats
Quart Cans (if single)
10 Quarts
Better buy gallons
💡 Purchasing Recommendation:
Purchase 3 one-gallon cans. Buying 1-gallon cans is significantly more economical than purchasing individual quarts.
How to Measure Room Surface Area for Paint
Calculate perimeter wall surface area by multiplying total wall length by height, then subtract openings:
$$\text{Wall Area} = 2 \times (\text{Length} + \text{Width}) \times \text{Height} - \text{Doors} (21\text{ sq ft}) - \text{Windows} (15\text{ sq ft})$$
- Standard Coverage: 1 US Gallon = 350 sq ft (Smooth walls) to 300 sq ft (Textured/Porous drywall).
- Rule of Thumb: Always round up to the nearest whole gallon to ensure matching dye lot color consistency.