Gallons per Square Foot Calculator
Calculate paint, coating, or liquid coverage for your project
Coverage rate refers to how much area a gallon of paint or coating material will cover. This depends on several factors:
- Material type and viscosity
- Surface porosity and texture
- Application method
- Required thickness
- Environmental conditions
Most manufacturers provide recommended coverage rates on their products, typically expressed in square feet per gallon.
To calculate the number of gallons needed:
Example calculations:
- For 400 sq ft area with 350 sq ft/gallon coverage: 400 ÷ 350 = 1.14 gallons
- With two coats: (400 ÷ 350) × 2 = 2.28 gallons
Pro Tip:
Always round up to the nearest gallon when purchasing materials to ensure you have enough for the entire project.
Surface Characteristics
- Porosity and absorption rate
- Texture and roughness
- Previous coatings or treatments
- Surface preparation quality
Application Method
- Brush application
- Roller application
- Spray application
- Professional vs. DIY application
Environmental Conditions
- Temperature during application
- Humidity levels
- Ventilation
- Direct sunlight exposure
Typical coverage rates for common materials:
- Interior Paint: 350-400 sq ft per gallon
- Exterior Paint: 250-300 sq ft per gallon
- Primer: 200-300 sq ft per gallon
- Concrete Sealer: 200-300 sq ft per gallon
- Wood Stain: 150-200 sq ft per gallon
- Epoxy Coating: 100-200 sq ft per gallon
Note: These are general guidelines. Always check the manufacturer's specifications for exact coverage rates.
Why do I need multiple coats?
Multiple coats ensure even coverage, better durability, and proper color development. Dark colors and porous surfaces often require additional coats for optimal results.
How do I measure irregular surfaces?
Break down irregular surfaces into basic geometric shapes, calculate each area separately, and sum them up. Add 10% for complex surfaces to account for additional coverage needs.
Should I buy extra material?
Yes, it's recommended to purchase 10-15% more material than calculated to account for touch-ups, mistakes, and varying surface conditions. This is especially important for custom-mixed colors.