Measure what gets coated
We turn the room perimeter and ceiling area into paintable square footage, subtract typical door and window openings, then add only the surfaces you select.
Interior paint estimator + bid checker
Know the paint.Check the quote.
Measure a room, price the work, and see whether a contractor quote lands in a sensible range before you buy a gallon or sign a bid.
No emailNo accountMethod shown
Free room estimate
Price your paint project
Your planning range333 sq. ft. selected
$525–$1,925professional project estimate
2gal. paint
1gal. primer
$140–$255DIY materials
7.5–13labor hours
Enter a contractor quote above to compare it. This is an educational range, not a bid.
See the assumptions behind this estimate
- Door and window counts are project totals; openings use 21 sq. ft. per door and 15 sq. ft. per window, never reducing wall area below zero.
- Smooth-surface paint coverage is 350-400 sq. ft. per gallon per coat; smooth applies a 100% coverage factor.
- Paint is rounded up to whole gallons separately for walls, ceilings, and trim so different products or colors are not treated as one can.
- Standard prep models 20% primer coverage at 200-300 sq. ft. per gallon.
- Labor is a single-painter equivalent and includes application, setup, cleanup, and standard prep; occupied rooms add handling time.
- Professional pricing uses broad $45-$90/hour billed-labor assumptions, a 1.00 regional factor, and overhead/margin. Taxes, major repairs, moving, lead/asbestos work, and unusual access are excluded.
- Quote price per square foot uses selected, uncoated paintable surface area, not floor area.
Paint + primerWhole gallons, not wishful fractions
Labor rangePrep and access included
Quote verdictContext, not contractor shaming
The math, with the lid off
How QuoteCoat estimates a room
Calculators should explain themselves. We show the surfaces, coverage assumptions, and cost drivers behind every range.
Adjust the real-world coverage
Coats, wall texture, prep condition, primer, and paint quality all change how far a gallon goes. QuoteCoat uses a range so one optimistic number cannot hide that uncertainty.
Build a quote range
Material cost is paired with estimated labor hours, project setup, occupancy, and a broad regional factor. Your contractor quote is compared with that range, not with a national average alone.
Coverage sources and safety reading
Manufacturer calculators are rough estimates, too. Check the can for your exact product and confirm unusual surfaces with a paint specialist.
Read the scope, not just the total
What moves a painting quote?
A fair quote is one you can compare line by line. Square footage starts the conversation; workmanship and scope finish it.
Check your quotePreparation
Patching, sanding, stain-blocking, caulk, and protecting floors can take longer than rolling the color itself.
Access
Tall walls, stairwells, built-ins, tight rooms, and occupied spaces add setup and careful movement time.
Finish level
A dramatic color change, glossy trim, damaged drywall, or a smooth sprayed finish can require more coats and detail work.
Local overhead
Insurance, wages, travel, scheduling, and warranty expectations vary. A higher bid is not automatically an unfair bid.
Before you choose a painter
Make every bidder price the same job.
Send each painter one short scope: rooms and surfaces, prep you can see, coats, paint line or allowance, moving furniture, protection, cleanup, timing, and warranty. Then compare.
- 1 Confirm prep and repairs
- 2 Name the paint and number of coats
- 3 Ask what is excluded
- 4 Verify insurance and references
Plain answers, no sales call
Painting calculator FAQ
The estimate is a strong starting point. Your walls, your product, and a clearly written scope are the final authority.
How accurate is this interior painting calculator?
It is a planning estimate, not a bid. Measurements and product coverage make the paint quantity useful, while the professional cost range is deliberately broad. Photos, a site visit, repairs, local labor, and finish expectations can move an actual quote.
Does one gallon really cover 400 square feet?
Sometimes. Major manufacturers commonly publish roughly 350–400 square feet per gallon for many interior paints, but the label for your exact product wins. Porous or heavily textured walls, application method, and strong color changes can reduce effective coverage.
Should I subtract every door and window?
For a useful room estimate, yes, but do not chase fractions of a square foot. QuoteCoat uses typical opening sizes. If a room has unusually large glass doors, wall-to-wall windows, or custom openings, measure those surfaces directly.
Why can two painting quotes be far apart?
Ask each painter to describe prep, coats, paint line, surfaces, repairs, protection, cleanup, schedule, warranty, and who buys materials. Quotes that sound identical often include different scopes.
What if my home was built before 1978?
Disturbing old painted surfaces can create hazardous lead dust. The U.S. EPA recommends lead-safe practices and, for covered paid work, a lead-safe certified firm. Treat sanding and demolition as a safety question, not just a pricing input.
Do you sell my project details to painters?
No. QuoteCoat does not ask for your email, phone number, address, or contractor’s name. The MVP is a decision tool, not a lead form. Basic anonymous product events may be counted to improve the calculator, but the numbers you type are not included in those events.