What it calculates
Estimate gallons needed for walls and multiple coats.
Paint Coverage Calculator
Estimate paint gallons from wall area, coats, coverage and waste.
Planning and estimating aid only. Verify project requirements, manufacturer instructions, adopted codes, permits, and field conditions before performing regulated work.
Painting estimating
How to Use This Calculator
Enter the measurements and job information you know, select Calculate, then use the result as a starting point for estimating, purchasing or project planning.
How the calculation works
Paintable area × coats is divided by coverage per gallon, then the waste percentage is added.
What the result means
Use the actual product coverage rate, especially on textured or porous surfaces.
Two coats on a measured wall area
For 320 square feet of net wall area, two coats and 350 square feet per gallon coverage, the base quantity is 320 × 2 ÷ 350 = 1.83 gallons. At 10% waste the result is about 2.01 gallons, so the tool’s whole-gallon purchase plan is 3 gallons.
Contractor tip: Enter wall area once and the number of coats separately. Do not double the area for two coats and also enter 2 coats; that would count the coats twice. Primer is separate.
Verify the final quantity
Coverage varies with surface texture, porosity, color change, application method and product. Use the coating manufacturer's stated spread rate for final purchasing.
Good practice: Compare the calculated quantity with plans, specifications, product packaging and current field conditions before purchasing material.