The Paint Calculator helps you estimate how many gallons of paint you need for a room or wall. Simply fill in the fields above and click Calculate to get an instant result.
This calculator is part of Calculate Wiki’s Construction Calculators collection.
What You’ll Need
- Wall Width (ft)
- Wall Height (ft)
- Number of Doors
- Number of Windows
- Number of Coats
- Paint Coverage (sqft/gal)
Formula Used
Paintable area = (Width × Height) − (Doors × 21 sq ft) − (Windows × 15 sq ft)
Paint needed (gallons) = (Paintable area × Coats) ÷ Coverage per gallon
Example Calculation
Using example inputs — Wall Width = 12 ft; Wall Height = 8 ft; Number of Doors = 1; Number of Windows = 1; Number of Coats = 2; Paint Coverage = 350 sqft/gal — the Paint Calculator returns:
| Value | Result |
|---|---|
| Paintable wall area | 60 sq ft |
| Total area to cover (with coats) | 120 sq ft |
| Paint needed | 0.34 gallons |
| Recommended purchase | 1 gallon can(s) |
0.5 gallons of paint. Based on 60 sq ft of wall area and 2 coat(s).
Helpful Information
Results from the Paint Calculator are estimates based on standard formulas used in the construction calculators field. For projects with significant cost, health, or safety implications, consider verifying results with a qualified professional.