Verified Mathematical Model & Formulation
Wall Area = 2 × (Length + Width) × Height Net Area = (Wall Area - Doors & Windows) × Coats Gallons = Net Area / 350 sq ft/gal
Calculates perimeter wall surface area, subtracts cutouts for standard doors (21 sq ft) and windows (15 sq ft), multiplies by coat count, and divides by typical 350 sq ft/gal coverage.
Configurable Parameters & Standard Units
- Room Length: (Default: 16 ft)
- Room Width: (Default: 12 ft)
- Ceiling Height: (Default: 8 ft)
- Number of Doors: (Default: 1 count)
- Number of Windows: (Default: 2 count)
- Number of Coats: (Default: 2 count)
Standard Worked Example & Practical Verification
Scenario: Room 14 ft × 12 ft with 9 ft ceilings, 2 windows, 1 door, applying 2 coats.
Calculated Solution
2.38 Gallons (Buy 3 Gallon Cans)
Practical Takeaway: Buy 3 single-gallon cans. The leftover partial gallon is ideal for future touch-ups.
Frequently Asked Questions
How much does one gallon of paint cover?
One gallon covers approximately 350 to 400 sq ft on smooth primed walls, or 250 to 300 sq ft on rough unprimed drywall or masonry.