Interior Painting Cost Calculator — Room by Room, DIY or Pro
Who this is for: For homeowners budgeting a repaint — and painters quoting jobs who want the math visible to the customer instead of a black-box number.
Room dimensions, coats and paint quality in — get paint gallons, material cost, and the full DIY vs pro breakdown.
Quick answer: Interior painting cost = wall area × coats ÷ 350 sq ft/gal × paint price, plus labor. A 12×12×8 bedroom (330 sq ft of wall) needs 2 gallons for two coats — about $85 DIY with premium paint, or roughly $1,400 with a pro at $4/sq ft. Enter your room below for the exact breakdown.
2026 painting cost by room size (DIY materials vs professional)
| Room | Wall area | Paint (2 coats) | DIY materials | Professional |
|---|---|---|---|---|
| Small bedroom 10×10 | 280 sqft | 2 gal | $55–90 | $420–980 |
| Bedroom 12×12 | 331 sqft | 2 gal | $65–110 | $500–1,150 |
| Primary bedroom 14×14 | 400 sqft | 3 gal | $80–140 | $600–1,400 |
| Living room 16×14×9 | 530 sqft | 4 gal | $105–180 | $800–1,850 |
| Kitchen (walls only) | 250 sqft | 2 gal | $50–85 | $375–875 |
Professional figures assume $1.50–3.50 per square foot of wall area (2026 US band); DIY figures assume premium paint at $37/gallon plus supplies. The calculator below prices your exact room.
2 standard
| Wall area | 2×(L+W)×H − doors(21) − windows(16) |
|---|---|
| Paint | Area × coats ÷ 350 sq ft/gal, round up |
| Paint price | Builder $20 · premium $37 · high-end $55/gal |
| Pro rate | $1.5–3.5/sqft of wall (default $2); $2–6/sqft is the floor-area band |
| Example | 12×12×8 room: 331 sqft → 2 gal → $85 DIY / ~$740 pro |
| Status | Figures follow 2026 US industry averages: pro interior $2–6/sq ft of wall area, coverage 350–400 sq ft/gal per coat, paint $15–60/gal by tier, exterior $1.5–5/sq ft. Estimates for budgeting — your local market and surface condition move the final number. |
How does this interior painting cost calculator work?
Three steps, all visible. Wall area: 2 × (length + width) × height minus doors (21 sq ft each) and windows (16 sq ft each). Paint: area × coats ÷ 350 sq ft per gallon, rounded up to buyable gallons, priced by tier (builder $20, premium $37, high-end $55/gal). Cost: DIY = materials + ~15% supplies; Pro = the same materials plus labor at the pro rate ($1.5–3.5/sq ft of wall area, $2 default — the $2–6/sq ft figures you'll see quoted are per floor area). Worked example — a 12×12×8 bedroom with one door and two windows: 330 sq ft of wall, 2 gallons for two coats, $74 in premium paint → about $85 DIY with supplies, or about $740 with a pro at $2/sq ft of wall. That gap is the whole decision, and the calculator shows both sides.
Common uses
- Budgeting a bedroom or living room repaint before getting quotes
- Comparing DIY material cost against a painter's quote line by line
- Checking how much a second coat actually adds
- Deciding between builder-grade and premium paint with real dollar differences
Where pro quotes hide their differences
Two painters can quote the same room 2× apart and both be honest: prep (patching, sanding, caulking) can double the hours; ceiling and trim inclusion adds 20–40%; premium paints cost them more but cover in one coat sometimes. When comparing quotes, ask three things — prep included? ceilings/trim included? how many coats? — then let this calculator price each answer.