Calculator Inputs
ft
ft
ft
sq ft
$
Results
352.00 sq ft
Total Wall Area
295.00 sq ft
Paintable Area
2 gallons
Paint Needed
$90.00
Estimated Cost
About This Calculator
This paint calculator helps you estimate how much paint you need for a single room. Simply enter your room dimensions, the number of doors and windows, and your desired number of coats to get an accurate estimate.
How It Works
- Calculates total wall area from room perimeter × wall height
- Subtracts ~21 sq ft per door and ~15 sq ft per window
- Multiplies by the number of coats for total coverage needed
- Divides by paint coverage per gallon to determine gallons needed
Pro Tips
- Always buy an extra gallon for touch-ups and mistakes
- Primer may reduce the number of paint coats needed
- Textured walls may require 10-20% more paint
- Dark-to-light color changes often need 3+ coats
Frequently Asked Questions
How much paint do I need for a 12x12 room?
For a standard 12×12 room with 8 ft ceilings, you need about 2 gallons of paint assuming 2 coats. This accounts for wall area minus 2 doors and 2 windows at typical coverage of 350 sq ft per gallon.
Should I buy an extra gallon?
Yes! It's always smart to buy 1 extra gallon. Paint batches can vary slightly in color, and you'll want matching paint for future touch-ups.
Does ceiling paint count?
This calculator focuses on wall paint. For the ceiling, measure the room area (length × width) and divide by your paint's coverage. A 12×10 room ceiling needs about 0.5 gallons.