Estimate paint, labor, and cost for interior rooms and exterior jobs. Enter dimensions, pick your surfaces, and get an instant breakdown. No sign-up required.
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Capture every room on a single job scope. Interior and exterior areas — from bedrooms to office suites — each with their own dimensions, surfaces, and prep work.
Set paint brands, sheen levels, and coverage rates per surface. PriceTable calculates exact quantities and generates a purchase list.
Masking, patching, caulking, power washing, scraping, and lead-safe prep — each with its own production rate and material cost.
Download a PDF or CSV purchase list with quantities aggregated by container size — ready to hand to your paint store.
Convert a job scope into a professional, line-itemized estimate. Send it by email or text while you're still on site.
See material cost, labor cost, and profit margin before sending the quote. Know which jobs actually make money.
Whether you're a homeowner tackling a weekend job or a professional painter pricing a residential job, the math behind a paint estimate follows the same fundamental steps: measure surfaces, subtract openings, figure out coverage, and account for waste. Understanding each step helps you buy the right amount of paint and avoid costly mid-job trips to the store.
Every estimate starts with geometry. For walls, you calculate the room's perimeter (the sum of all wall lengths) and multiply it by the ceiling height. A 12 × 16 foot room with 9-foot ceilings has a total wall area of (12 + 16 + 12 + 16) × 9 = 504 square feet before exclusions.
Ceilings are simpler: length × width. Trim is usually expressed as the baseboard perimeter times the baseboard height — a common rule of thumb is 6 inches (0.5 ft) of baseboard around the perimeter. Interior doors are estimated at about 20 square feet of paintable area each. Exterior doors are larger: this calculator uses 21 square feet for an entry or patio door and 105 for a garage door.
You don't paint over windows and doorways, so their area must be subtracted from the wall total. A standard window opening is roughly 15 square feet, and a standard door opening is about 20 square feet. A room with two windows and one door would lose (2 × 15) + (1 × 20) = 50 square feet from the total wall area, bringing our example room from 504 down to 454 square feet of paintable wall space.
Paint coverage depends on the application method and the surface condition, so this calculator uses a coverage table keyed to both rather than a single number. Interior drywall covers 350 square feet per gallon brushed and 400 sprayed. Porous substrates go a long way down — brick is 150 brushed — while smooth metal and vinyl reach 450 sprayed. Across every substrate and method the table spans 150 to 450 square feet per gallon. The Coverage rate line in the calculator's formula breakdown always prints the exact figure used for your inputs.
Textured surfaces, porous substrates, and dark-to-light color changes will all reduce effective coverage. Always add a waste factor — 10% is the standard minimum — to account for touch-ups, drips, and roller tray loss.
One coat is rarely enough. Fresh drywall, color changes, and semi-transparent finishes almost always require two coats for even coverage. If you're going from a dark color to a light one, three coats is common. The number of coats is a direct multiplier on both your paint quantity and your production time: 454 sq ft × 2 coats = 908 sq ft of coverage to buy, and 908 square feet to roll out.
Primer is a separate consideration from paint coats. Porous substrates (new drywall, concrete, brick) and bare surfaces strongly benefit from a dedicated primer coat applied before paint. Primer seals the surface, improves adhesion, and ensures even color. It's calculated separately: primer coverage is typically about 400 sq ft/gal. For the example room, that's 454 ÷ 400 × 1.10 waste = 1.3 gallons of primer, plus about 2.6 hours of additional labor (454 ÷ 175 sq ft/hr). Because primer is a single coat, it is never multiplied by the coat count.
Professional painters use production rates — the number of square feet a single painter can cover in an hour, per coat — to estimate labor. Rates are quoted per coat because a second coat is a second pass over the same surface: a two-coat job takes about twice the production time of a one-coat job on the same wall. Typical rates for interior work are:
This calculator uses 150 sq ft/hr for walls, 120 for ceilings, 100 linear feet per hour for trim, and the full 45 minutes per door. Booking the second coat as real labor, rather than as a little extra paint, is the single biggest difference between an estimate that holds and one that loses money on a job you won. Spray application is typically 30–40% faster than brush and roll on large open surfaces, but requires more prep time for masking, which the prep options add back separately.
The total cost of a painting job is the sum of materials (paint, primer, tape, drop cloths, roller covers) and labor. Material costs range from $25 to $75 per gallon depending on quality, with premium brands like Benjamin Moore Regal or Sherwin-Williams Emerald at the higher end. Labor rates for professional painters typically range from $40 to $65 per hour depending on market, complexity, and crew size.
Enter 12 × 16 above and leave every other field at its default, and you can follow each step: 9-foot ceilings, two windows and one door excluded — 454 sq ft of paintable wall. Walls only, two coats, brush and roll, mid-grade paint, with the default masking and protection prep left on.
Larger rooms, higher ceilings, and additional surfaces push the price up proportionally. If your own numbers come in materially below this, check whether you've booked the second coat as real labor — that is where most under-priced bids go wrong.
Exterior estimates follow the same area-to-gallons logic, but the variables change. Instead of room length and width, you work with the building's perimeter and wall height, multiplied by the number of stories. Exterior substrates — wood siding, stucco, brick, fiber cement — have different coverage rates than interior drywall, with porous surfaces like stucco and brick consuming significantly more paint per square foot.
Openings come off the wall total outdoors just as they do indoors, sized the way a painter measures them: a standard window at 3 × 4 feet, an entry or patio door at 3 × 8, and a single garage door at 8 × 7. On a 40 × 30 house, six windows, two entry doors and one garage door take 176 square feet off the walls.
Access difficulty matters for exterior work. Two-story homes require ladders or scaffolding, which slows production rates by 50% compared to ground-level work. Three-story buildings are even slower. These multipliers are built into professional estimates but easy to forget when hand-calculating.
Exterior jobs also include surfaces rarely seen indoors: soffits and eaves (calculated as perimeter × soffit depth), trim and fascia (linear feet of perimeter plus door casings), fences (length × height × sides), and decks (floor area plus railings and stairs). Each surface has its own area formula and production rate.
Prep work is heavier outdoors. Power washing is standard on nearly every exterior repaint — expect about 500 square feet per hour. Scraping and sanding peeling paint, caulking gaps around trim and door casings, and wood repair are all common. Budget 3–6 additional hours of prep on a typical exterior compared to a comparable interior.
For a single room, mental math and a calculator work fine. But when you're pricing a 15-room repaint with different ceiling heights, multiple paint colors, exterior elevations, and prep work, the complexity multiplies fast. Professional painting estimating software like PriceTable automates the math, tracks brand preferences and coverage rates, generates purchase lists, and produces professional estimates — all from a single job scope. The calculator above gives you a solid starting point; the full platform handles the rest.
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