How we estimate interior painting cost
Every estimate combines a national price for each part of the job with a local labor adjustment for your state. Here is exactly how that works and where the numbers come from.
The formula
For each line item we multiply a quantity (driven by your wall area, number of coats, prep level, and paint grade) 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 | ref |
| Primer coat | $0.25 / sq ft | ref |
| Wall paint | $0.13 / sq ft | ref |
| Wall painting labor | $0.45 / sq ft | ref |
| Ceilings | $0.75 / sq ft | ref |
| Trim, doors & windows | $3.50 / sq ft | ref |
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 & 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/oes/current/oes472141.htm
- https://www.thisoldhouse.com/painting/interior-painting-cost