Paint Calculator
Gallons needed for walls, doors and windows deducted.
Enter your values
Results update instantly as you type — no submit needed.
Results
- Paint needed
- 2.42 gallons
- Buy
- 3 gallons
- Paintable wall area
- 453 sq ft
- Primer if bare drywall
- 1.51 gallons
Quick answer
One US gallon of paint covers about 350–400 square feet per coat on primed drywall.
Gallons = wall area × coats ÷ 375
How to use the Paint Calculator
- 1Measure the perimeter of the room.
- 2Enter the wall height and openings.
- 3Choose how many coats you plan to apply.
Frequently asked questions
How much does a gallon cover?
About 375 sq ft per coat on smooth primed walls; textured or porous surfaces can drop to 250 sq ft.
Do I need primer?
Yes on bare drywall, over strong colour changes and on stained or patched areas — otherwise a self-priming paint is fine.