Worked example
How Much Paint for a 12x12 Room?
This example embeds the paint calculator with a 12 ft by 12 ft room, 8 ft walls, and two coats.
Painting
Calculator inputs
Paint Calculator Results
Results update in your browser as you edit inputs.
Enter project dimensions to calculate material quantity.
Inputs used in this example
- Room size: 12 ft by 12 ft.
- Wall height: 8 ft.
- Coats: 2.
- Paint coverage: 350 sq ft per gallon.
Expected output
The calculator estimates 384 sq ft of wall area and about 2.2 gallons for two coats before any waste factor.
Formula explanation
- Find room perimeter with 2 x (width + length).
- Multiply perimeter by wall height for wall area.
- Multiply by number of coats.
- Divide by coverage per gallon.
Main calculator
Use the full Paint Calculator to change dimensions, waste factor, and optional user-entered unit price.
FAQ
Does this subtract doors and windows?
No. This quick estimate uses full wall area.
Should I round up gallons?
For buying paint, most people round up to the next practical container size after checking the product label.