Worked example
How Much Paint for a 10x10 Room?
This example estimates wall paint for a 10 ft by 10 ft room with one door, two windows, 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: 10 ft by 10 ft.
- Wall height: 8 ft.
- Openings: one 20 sq ft door and two 15 sq ft windows.
- Coats: 2, with 350 sq ft per gallon coverage.
Expected output
The calculator estimates 320 sq ft of wall area, subtracts 50 sq ft of openings, and needs about 1.54 gallons before rounding for two coats.
When to adjust this example
- Leave door and window counts at 0 for a faster full-wall estimate.
- Increase waste or lower coverage for rough, patched, porous, or strongly colored walls.
- This example does not include ceiling paint, trim paint, primer, drop cloths, tape, rollers, or brushes.
Formula explanation
- Find wall area from 2 x (10 + 10) x 8.
- Subtract the entered door and window area.
- Multiply paintable wall area by two coats.
- Divide by coverage per gallon and round practical purchase quantity up.
Main calculator
Use the full Paint Calculator to change dimensions, waste factor, and optional user-entered unit price.
FAQ
Should I always subtract windows and doors?
Not necessarily. For quick planning, leaving them at 0 can create a small cushion. Subtract them when openings are large.
Does this include primer?
No. Add primer separately when the surface or color change requires it.