Gallons per Square Foot Calculator
Calculate paint, coating, or liquid coverage for your project
Gallons per Square Foot Calculator
Table of Contents
Understanding Coverage Rates
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.
How to Calculate Coverage
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.
Factors Affecting Coverage
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
Common Materials Coverage
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.
Frequently Asked Questions
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.