The formula
For each line item we multiply a quantity by a national unit cost, then apply a quality-grade factor. A regional labor multiplier is applied to the labor portion only; materials are priced nationally. We show the itemized result as a ±18% range.
National unit costs
| Line item | National unit cost | Source |
|---|---|---|
| Surface prep & masking | $0.35 / sq ft | homeguide.com (source for Surface prep & masking) |
| Primer coat | $0.25 / sq ft | thisoldhouse.com (source for Primer coat) |
| Wall paint | $0.13 / sq ft | thisoldhouse.com (source for Wall paint) |
| Wall painting labor | $0.45 / sq ft | thisoldhouse.com (source for Wall painting labor) |
| Ceilings | $0.75 / sq ft | homeguide.com (source for Ceilings) |
| Trim, doors & windows | $3.50 / sq ft | homeguide.com (source for Trim, doors & windows) |
Regional labor multipliers
Each state's labor multiplier is its mean painter wage relative to the national mean (BLS OEWS Painters, Construction & Maintenance, SOC 47-2141). Multipliers are bounded to a sane range and applied to the labor share of each line item, so materials stay nationally priced while labor tracks local wages.
Data vintage and limitations
Compiled June 2026 from public cost aggregators and government wage data. These are derived estimates, not live contractor quotes. Local prices vary with project complexity, access, and material availability; always confirm with a licensed contractor before budgeting.
Sources
- https://homeguide.com/costs/cost-to-paint-a-ceiling
- https://homeguide.com/costs/cost-to-paint-interior-of-house
- https://homeguide.com/costs/cost-to-paint-trim-baseboards
- https://taxfoundation.org/data/all/state/sales-tax-rates-midyear-2025/
- https://www.bls.gov/ooh/construction-and-extraction/painters-construction-and-maintenance.htm
- https://www.thisoldhouse.com/painting/interior-painting-cost