Paint Gallons Calculator Pro (USA)
Accurate Estimates for Interior Walls & Ceilings
Room Dimensions (Feet)
Details
Standard USA coverage is 350-400 sq ft.
Total Paint Needed
0
Gallons
Total Wall Area: 0 sq ft
Total Ceiling Area: 0 sq ft
Windows/Doors Deduction: 0 sq ft
Paintable Surface: 0 sq ft
Top View
Live Room Ratio Visualization
Expert Guide: How to Calculate Paint for Your Room
Calculating the right amount of paint is crucial for budget management and ensuring a smooth finish. Our Paint Gallons Calculator Pro (USA) uses standard industry measurements to provide accurate estimates.
Pro Tip: Always buy slightly more paint than calculated (usually 10% extra) to account for touch-ups, spillage, and differences in surface texture.
Understanding the Math
We calculate the total surface area of your walls and subtract the area of openings.
- Wall Area: (Length + Width) × 2 × Height
- Ceiling Area: Length × Width
- Standard Deductions: We assume an average window is 15 sq ft and a standard door is 20 sq ft.
Why Coverage Matters
Most paint cans in the USA state coverage between 350 to 400 square feet per gallon. However, porous surfaces like drywall or unprimed wood may absorb more paint, reducing the coverage rate. Our calculator defaults to 350 sq ft to ensure you don’t run out of paint.
Steps for a Perfect Paint Job
- Measure your room length, width, and wall height accurately.
- Count all windows and doors that won’t be painted.
- Decide if you are painting the ceiling.
- Use this calculator to get your gallon estimate.
- Apply a high-quality primer for better color accuracy.
