Paint Coverage Calculator
Accurate paint estimation prevents mid-project trips and batch-matching problems. This calculator uses standard coverage rates to determine gallons needed based on wall area, surface texture, number of coats, and paint type.
Room / Area Details
Coverage rates assume proper surface preparation. Porous surfaces, extreme color changes, and high-build coatings may require additional material.
Standard Paint Coverage Rates
| Surface | Coverage per Gallon |
|---|---|
| Smooth drywall (painted) | 350–400 ft² |
| Orange peel / light texture | 250–350 ft² |
| Heavy knockdown / stucco | 200–300 ft² |
| Bare drywall (primed) | 300–350 ft² |
| Bare wood | 200–300 ft² |
| Exterior siding | 250–350 ft² |
Frequently Asked Questions
How many gallons of paint for a 12×12 room?
A 12×12 room with 8-foot ceilings has about 342 net square feet of wall area (after deducting 2 openings). At 400 sq ft per gallon, that is about 0.85 gallons per coat — round up to 1 gallon per coat, 2 gallons total for two coats.
Do I need primer?
Primer is recommended for: bare drywall, bare wood, stain blocking, dramatic color changes (dark to light), and high-gloss over flat. Many premium paints include primer, but a dedicated primer provides better results on new surfaces.
References & Methodology
- Paint Quality Institute (PQI), "Paint Coverage and Application Guidelines," paintquality.com. — Standard paint coverage rates (350–400 sq ft per gallon) and coat requirements by surface type.
- U.S. Environmental Protection Agency (EPA), "Lead Renovation, Repair, and Painting (RRP) Rule," epa.gov. — Lead paint safety requirements for pre-1978 homes affecting project scope and cost.
- RSMeans by Gordian, "Interior and Exterior Painting Costs," 2024. — Regional labor and material cost benchmarks for residential painting by surface type and finish level.
References
- 28 CFR Part 35 — Nondiscrimination on the Basis of Disability in State and Local Government Services
- Advisory Council on Historic Preservation — Section 106 of the National Historic Preservation Act
- ADA Standards for Accessible Design — U.S. Department of Justice
- 2010 ADA Standards for Accessible Design — U.S. Department of Justice
- Centers for Medicare & Medicaid Services (CMS)
- 21 CFR Part 177 — Indirect Food Additives: Polymers, U.S. FDA / Electronic Code of Federal Regulatio
- 28 C.F.R. Part 36 — Nondiscrimination on the Basis of Disability, ecfr.gov
- ASHRAE Climate Zone Map — U.S. Department of Energy Building America Program