Use this focused calculator when only one wall receives a distinct color or coating. Primer and specialty finishes should be calculated separately when required.
01 / Formula
How this is calculated
Gallons = ((wall width × height) − openings) × coats ÷ coverage02 / Assumptions
What the estimate assumes
- ✓The wall is rectangular.
- ✓A standard door subtracts 20 sq ft and a standard window 15 sq ft.
- ✓Coverage is entered from the selected product.
03 / Worked example
See the math in context
A 14 × 8 ft wall with one window has 97 net sq ft; two coats create 194 coated sq ft.
04 / Guidance
Plan color transitions
Inside corners, outside corners, ceilings and trim define where the accent color stops. Masking and cutting accuracy affect the finished scope but not wall area.
Questions
Frequently asked
Should I round up when buying paint?+
Yes. Paint is sold in fixed container sizes, and a small reserve helps with touch-ups, porous surfaces, and application loss. The calculator shows both the theoretical quantity and a practical purchase amount.
Does paint coverage include two coats?+
Coverage printed on a can is normally stated per coat. Two coats cover the same surface twice, so the calculator multiplies net area by the number of coats before dividing by the selected coverage rate.