🎨 Paint Calculator
Calculate gallons of paint needed for a room
How Paint Calculation Works
Formula
Gallons = (Wall Area − Openings) × Coats / 350
- 1Enter room dimensions (length, width, ceiling height).
- 2The calculator computes total wall area from the perimeter.
- 3Door and window areas are subtracted (21 sq ft per door, 15 sq ft per window).
- 4The paintable area is multiplied by the number of coats.
- 5Total area is divided by 350 sq ft/gallon coverage to get gallons needed.
About Paint Calculator
Calculate how much paint you need for a room. Enter wall dimensions, doors, and windows to get the exact number of gallons for your project.
Frequently Asked Questions
How much area does a gallon of paint cover?
One gallon of paint covers approximately 350-400 square feet on smooth surfaces. Textured or porous surfaces may require more paint, reducing coverage to 250-300 sq ft.
How many coats of paint do I need?
Most paint jobs need 2 coats. Going from dark to light colors or using a new color may require a primer plus 2 coats. High-quality paints with built-in primer may need only 1-2 coats.
Should I buy extra paint?
Always buy at least 10% extra for touch-ups and waste. Keep leftover paint for future touch-ups — store it sealed at room temperature.