Paint quality
A premium paint may cost more per gallon but can cover more evenly or combine paint and primer. Use the coverage and price printed for the product you plan to buy.
Room planning / Cost calculator
Paint Cost Calculator
Build a practical paint budget from your room dimensions, openings, coverage, coats, and labor choice. Change an assumption and the estimate updates immediately.
Painting several interior rooms? Use the Interior Paint Cost Calculator for a room-by-room home estimate. Painting siding or exterior walls? Use the Exterior Paint Cost Calculator for a separate outside-only estimate.
U.S. customary units/No signup needed/Planning estimate, not a quote
Start with the room
Use the inside wall-to-wall length and width. Doors and windows are deducted automatically; add unusual openings below.
Planning estimate only. Product coverage, local prices, wall condition, and contractor scope can change the final cost.
How the number works
A cost formula you can inspect.
There is no hidden square-foot shortcut. The calculator shows the surfaces, coverage assumptions, and labor basis behind the total.
Material cost uses whole gallons to buy. Professional labor uses the selected paintable surface area—not the number of gallons.
Planning comparison
Two rooms, two useful starting points.
These examples use two coats, one door, and two windows. The larger room includes its 144 sq ft ceiling.
| Scenario | Paintable area | Paint to buy* | Paint cost* | Pro labor* |
|---|---|---|---|---|
| 10 × 12 × 8 ft | 302 sq ft | 2–3 gal | $50–$195 | $302–$906 |
| 12 × 12 × 8 ft | 478 sq ft | 3–4 gal | $75–$260 | $478–$1,434 |
*Planning assumptions, not quotes: 250–400 sq ft per gallon, $25–$65 per gallon, and $1–$3 per paintable square foot for professional labor. Whole-gallon ranges are rounded up.
Read the estimate correctly
What moves the paint budget.
The same room can have a different budget depending on the product, prep, and scope. These are the assumptions worth checking before you shop.
Number of coats
One coat may work for a close color on sound walls. Two coats is a practical planning baseline for a color change; deep colors and patchy surfaces may need more.
Primer
Primer is most useful on new drywall, stains, glossy surfaces, porous repairs, or a strong color change. It is calculated separately because its coverage and price differ from paint.
Ceiling
Ceiling paint is not automatic. Turn it on when the scope includes the ceiling; the calculator adds the room’s length × width to the paintable area.
Trim
Baseboards, casings, and other trim are tracked as a separate surface. Measure their paintable area and use the trim product’s coverage rather than guessing from wall area.
Labor
DIY labor is zero in the estimate, while professional labor multiplies paintable square feet by your planning rate. Contractor quotes may include prep, protection, travel, and minimum charges.
Surface condition
Filling holes, sanding, caulking, peeling-paint removal, mildew treatment, and stain blocking can add materials and time that a simple area formula cannot price.
Worked examples
Check the math against a familiar room.
10 × 12 × 8 ft / DIY
Two walls runs around the room: 2 × (10 + 12) × 8 = 352 sq ft. One door and two windows deduct 50 sq ft, leaving 302 wall sq ft. At two coats and 350 sq ft per gallon, you need 1.73 gallons, so plan to buy 2 whole gallons. At $42 per gallon, materials are $84.
12 × 12 × 8 ft / Pro + primer
Walls leave 334 sq ft after one door and two windows. Add the 144 sq ft ceiling for 478 paintable sq ft. Two coats at 350 sq ft per gallon means 3 paint gallons ($126). One primer coat at 300 sq ft per gallon means 2 primer gallons ($50). At $1.75 per paintable sq ft, labor is $836.50, for an estimated total of $1,012.50.
Before you buy
Frequently asked questions about paint costs.
Does the calculator deduct doors and windows?
Yes. It deducts 20 sq ft per door and 15 sq ft per window, then lets you add a custom opening-area deduction for built-ins, arches, or unusually large openings.
Should I include the ceiling?
Only if you plan to paint it. Turning on the ceiling adds the room’s floor area to the paintable surface and to the paint and primer gallons.
Why does the calculator round gallons up?
Paint is generally purchased in whole-gallon containers in this planning model. Rounding up avoids a shortfall, though the best product mix may include quarts or larger containers.
What does professional labor include?
It is a transparent planning rate multiplied by paintable square feet. Real quotes can add prep, masking, furniture moving, repairs, minimum job charges, and local market differences.
Can I save or share this estimate?
Yes. Save stores the numeric project in this browser with no account. Share uses your device’s Web Share sheet when available and otherwise copies a short estimate summary.
Keep planning
Related Builexa Tools and Guides
Builexa · Home project planning
Paint Cost Calculator
Estimated total $84.00 — 2 paint gallons to buy
Estimate details
- Paintable surface
- 302 sq ft
- Paint
- 2 gal · $84.00
- Primer
- 0 gal · $0.00
- Trim paint
- 0 gal · $0.00
- Labor
- $0.00
Inputs and assumptions
10 × 12 × 8 ft, 1 door(s), 2 window(s), 2 coat(s). Coverage: 350 sq ft per gallon at $42.00 per gallon.
Planning estimate only. Verify measurements, product specifications, local prices, and site conditions before purchase.