Rex says
Money math without the spreadsheet headache. Plug in your numbers and I'll show you exactly where the dollars land.
Try a scenario
Click to load — tweak from there.Inputs
Result
Total interior painting cost
$2,268
Labor
$1,980
Paint material
$288
Gallons to buy
6
Cost per sq ft of wall
$2.52
Psst — share this and help Rex grow
One click, a permanent link with your numbers baked in.
How to use this
- 1Enter total wall area to paint (sq ft).
- 2Enter coats.
- 3Enter labor rate per sq ft per coat ($).
- 4Enter prep condition.
- 5Enter paint price per gallon ($).
- 6Enter coverage per gallon (sq ft).
- 7Read your total interior painting cost on the right — it updates as you type.
- 8Hit Share to keep the scenario or send it to someone.
About this calculator
Interior painting is priced two ways: per square foot of wall area, or per room. Pros quote from wall area because that is what actually drives labor — a 12x12 room with 9-foot ceilings has roughly 430 square feet of wall, and a painter covering about 175 square feet per hour with cut-in work spends far longer on a room with heavy patching, trim, or dark colors needing three coats. This calculator takes your total painted wall area, the number of coats, a prep condition multiplier for patching and caulking, and your local labor rate, then adds paint at roughly 350 square feet of coverage per gallon. 2026 US national averages land near $2.00-$4.50 per square foot of wall area for walls-only work with mid-grade paint, higher when ceilings and trim are included. Enter your own painter's quote rate to compare bids honestly.
Worked example
Using the values the calculator loads with:
Inputs
- Total wall area to paint: 900 sq ft
- Coats: 2
- Labor rate per sq ft per coat: 1.1 $
- Prep condition: Normal — minor patching
- Paint price per gallon: 48 $
- Coverage per gallon: 350 sq ft
Results
- Total interior painting cost: $2,268
- Labor: $1,980
- Paint material: $288
- Gallons to buy: 6
- Cost per sq ft of wall: $2.52
What each field means
Inputs
- Total wall area to paint (sq ft)
- The total wall area to paint used in the calculation, measured in sq ft. Starts at 900 sq ft so you have a working example on load. Accepted range: 50–20000 sq ft.
- Coats
- The coats used in the calculation. Starts at 2 so you have a working example on load. Accepted range: 1–4.
- Labor rate per sq ft per coat ($)
- The labor rate per sq ft per coat used in the calculation, measured in $. Starts at 1.1 $ so you have a working example on load. Accepted range: 0.3–4 $.
- Prep condition
- Pick the option that matches your situation — the maths changes per option. Choices: Clean new drywall — light prep, Normal — minor patching, Heavy patching, caulking, sanding, Damaged walls / wallpaper removal.
- Paint price per gallon ($)
- The paint price per gallon used in the calculation, measured in $. Starts at 48 $ so you have a working example on load. Accepted range: 15–120 $.
- Coverage per gallon (sq ft)
- The coverage per gallon used in the calculation, measured in sq ft. Starts at 350 sq ft so you have a working example on load. Accepted range: 200–450 sq ft.
Results
- Total interior painting cost
- Returned as a money amount in US dollars and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Labor
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Paint material
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Gallons to buy
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Cost per sq ft of wall
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
How do I figure my wall area?
Add the length of every wall in the room, multiply by ceiling height, then subtract roughly 20 sq ft per door and 15 sq ft per average window. Painters usually skip the deductions on small openings because cut-in work around them takes just as long.
Do dark colors really cost more?
Often yes — deep reds, navies, and going from dark to light frequently need a tinted primer plus three coats instead of two, which is a 50% jump in both paint and labor.
Is per-room pricing ever better?
For a single small room, flat per-room pricing (commonly $350-$800 for a bedroom in 2026) can beat square-foot math because it bundles setup and travel. For whole-house work, square-foot pricing is usually more honest.
Accuracy and limitations
- Results are estimates before tax, fees, and inflation unless an input explicitly covers them.
- Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.
- This is educational maths, not financial advice. Check anything contractual with the lender or your accountant.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Interior Painting Cost Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/interior-painting-cost
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/interior-painting-cost" target="_blank" rel="noopener">Interior Painting Cost Calculator — RevenueLab</a> (2026).</p>
Source: [Interior Painting Cost Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/interior-painting-cost) (2026).