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. They are planning estimates, not complete shopping lists.
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.
When to adjust this example
- Add waste or adjust coverage for rough, porous, patched, or strongly colored walls.
- Check actual container sizes before buying paint.
- This example estimates wall paint only, not primer, trim paint, ceiling paint, or tools.
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.