Paint Calculator

Estimate paint gallons needed for any room including doors, windows, and coats.

How to Use the Paint Calculator

  1. Enter room length, width, and height.
  2. Enter number of doors and windows.
  3. Set coats and paint cost per gallon.

Paint estimation

Gallons = (Wall area − Openings) × Coats ÷ 350. Wall area = 2 × Height × (Length + Width). Always buy slightly extra for touch-ups.

Frequently Asked Questions

How many sq ft does a gallon cover?
We use 350 sq ft per gallon as a standard estimate for one coat on smooth surfaces.
Are doors and windows deducted?
Yes — each door deducts ~20 sq ft and each window ~15 sq ft from wall area.

Related Tools