🎨 Gallons per Square Foot Calculator
Calculate gallons per square foot for paint, coatings, and materials
Square feet covered per gallon (typically 250-400 sq ft/gallon)
How to Use This Calculator
Select Calculation Type
Choose paint coverage, coating coverage, or spread rate depending on your application.
Enter Area
Input the total area to be covered in square feet. Measure all surfaces that need coverage.
Enter Coverage Rate
Enter the coverage rate from the product label. For paint, typically 250-400 sq ft per gallon. For coatings, enter square feet per gallon at 1 mil thickness.
Calculate and Review
Click "Calculate Gallons" to see gallons needed, quarts, pints, and coverage information. Use this for material planning and purchasing.
Formula
Paint: Gallons = (Area / Coverage Rate) × Number of Coats
Coating: Gallons = (Area × Thickness) / Coverage Rate
Spread Rate: Gallons per sq ft = 1 / Coverage Rate
Example 1: Paint Coverage (1,000 sq ft, 350 sq ft/gallon, 2 coats)
Step 1: Gallons per coat = 1,000 / 350 = 2.86 gallons
Step 2: Total gallons = 2.86 × 2 = 5.72 gallons
Step 3: Quarts = 5.72 × 4 = 22.88 quarts
Step 4: Order: 6 gallons (round up)
Example 2: Coating Coverage (500 sq ft, 4 mils, 1,600 sq ft/gallon/mil)
Step 1: Coverage at 1 mil = 1,600 sq ft/gallon
Step 2: Coverage at 4 mils = 1,600 / 4 = 400 sq ft/gallon
Step 3: Gallons = 500 / 400 = 1.25 gallons
Step 4: Quarts = 1.25 × 4 = 5 quarts
About Gallons per Square Foot Calculator
The Gallons per Square Foot Calculator is an essential tool for contractors, painters, and DIY enthusiasts who need to calculate material coverage rates for paint, coatings, and other liquid materials. This calculator eliminates guesswork by providing accurate gallon calculations based on area, coverage rate, number of coats, and coating thickness, helping you order the correct amount of materials.
When to Use This Calculator
- Material Planning: Calculate paint, coating, or material gallons needed per square foot
- Coverage Estimation: Estimate material coverage based on product specifications
- Cost Calculation: Estimate material costs based on area and coverage rates
- Project Budgeting: Budget for paint, coating, and material costs
- Purchase Planning: Determine exact quantities to order from suppliers
Why Use Our Calculator?
- ✅ Multiple Calculation Types: Supports paint, coating, and spread rate calculations
- ✅ Accurate Formulas: Uses standard coverage rate formulas
- ✅ Complete Conversions: Shows gallons, quarts, and pints
- ✅ Thickness Support: Includes coating thickness calculations
- ✅ Time Savings: Instant calculations eliminate manual math
Understanding Coverage Rates
Paint Coverage: Paint coverage typically ranges from 250-400 square feet per gallon depending on paint type, surface texture, and application method. Latex paint covers 300-400 sq ft/gallon, while oil-based paint covers 250-300 sq ft/gallon. Rough surfaces require more paint than smooth surfaces.
Coating Coverage: Coating coverage is specified per mil thickness. For example, a coating that covers 1,600 sq ft/gallon at 1 mil thickness covers 400 sq ft/gallon at 4 mils thickness. Coverage decreases proportionally with thickness.
Spread Rates: Spread rate is the inverse of coverage rate—it shows gallons per square foot. For paint with 350 sq ft/gallon coverage, the spread rate is 1/350 = 0.00286 gallons per square foot.
Tips for Best Results
- Check Product Label: Use coverage rates from product labels for accuracy
- Account for Waste: Add 10% extra for waste, spillage, and cleanup
- Consider Surface Type: Rough surfaces require more material than smooth surfaces
- Multiple Coats: Account for number of coats when calculating paint needs
- Round Up: Always round up to nearest gallon or quart to ensure you have enough
Frequently Asked Questions
How many gallons of paint do I need per square foot?
Paint coverage typically ranges from 250-400 sq ft per gallon, so gallons per square foot range from 0.0025-0.0040. For example, if paint covers 350 sq ft/gallon, you need 0.00286 gallons per square foot. The calculator determines exact gallons based on total area and coverage rate.
How do I calculate coating gallons per square foot?
For coatings, calculate coverage based on thickness: Coverage at thickness = Coverage at 1 mil / Thickness. For example, if a coating covers 1,600 sq ft/gallon at 1 mil, it covers 400 sq ft/gallon at 4 mils. Gallons = Area / Coverage at thickness. The calculator includes coating thickness calculations.
What is a typical paint coverage rate?
Typical paint coverage is 300-400 sq ft per gallon for latex paint on smooth surfaces, and 250-300 sq ft per gallon for oil-based paint. Rough surfaces, porous materials, and dark colors require more paint. Always check the product label for specific coverage rates.
How much paint do I need for multiple coats?
Multiply single-coat gallons by the number of coats. For example, if one coat requires 3 gallons, two coats require 6 gallons. The calculator automatically accounts for multiple coats when you enter the number of coats.
Should I add extra paint for waste?
Yes, always add 10-15% extra paint for waste, spillage, cleanup, and mistakes during application. If you calculate 10 gallons needed, order 11-12 gallons to ensure you have enough material. The calculator shows exact amounts—add 10% when ordering.