How much does it cost to paint a room? Calculate the complete cost of your painting project including paint, primer, and all necessary supplies.
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Last updated March 31, 2026 by our expert review team
$28
per gallon
350 sq ft coverage
$40
per gallon
400 sq ft coverage
$55
per gallon
450 sq ft coverage
Cherry Jane Limbago
Licensed Civil Engineer & Master Plumber
Licensed civil engineer and master plumber with 10+ years in structural design, estimation, and project management. Currently Project Engineer at Universal Robina Corporation.
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Certified Cost & Estimating Professional
AACE-certified estimator working with 20+ insulation companies including the two largest franchises in America.
See full profileUpdated March 2026
How we verify our calculatorsPremium paint costs more per gallon but covers more area and typically needs fewer coats, often making it cheaper overall.
Benjamin Moore Regal Select ($55-65/gal) and Sherwin-Williams Duration ($65-75/gal) cover in 1 coat on most colors, saving $15-25/gal over buying 2 gallons of cheap paint that needs 2 to 3 coats.
Professional painters charge $2-4/sq ft in the Midwest and $4-7/sq ft in coastal cities. Get 3 quotes; rates vary 40% even within the same metro area.
Prep work accounts for 60 to 80% of a pro painter's time. Expect $0.50-1.50/sq ft for patching, sanding, caulking, and taping. Skipping prep leads to peeling within 1 to 2 years.
DIY a 12x12 room for $80-150, or hire a pro for $400-800. Below 2 rooms, DIY saves money; above 3 rooms, a pro's speed makes hiring worthwhile.
Behr Ultra ($35/gal at Home Depot) is the best mid-range value. Consumer Reports rates it equal to paints costing $20 more.
Buy all your paint at once and have the store shake it into a single 5-gallon bucket (called "boxing"). This eliminates color variation between gallons.
Painting trim? Our baseboard calculator estimates how many linear feet of baseboard you need before painting.
Our paint cost calculator estimates your total project cost by calculating the paintable wall area (height x perimeter minus door and window cutouts), then determining gallons needed based on paint quality coverage rates and coat count. For a simpler quantity-only estimate, try our paint calculator. Economy paint covers ~350 sq ft/gal, standard covers ~400 sq ft/gal, and premium covers ~450 sq ft/gal. These numbers come from manufacturer specs for smooth drywall. For textured walls, reduce coverage by 20-25%. The calculator uses standard deductions of 20 sq ft per door and 15 sq ft per window, which match typical 3'x6'8" doors and 3'x5' windows in US residential construction.
Formula
Paintable Area = (Height x Perimeter) - (Doors x 20 sq ft) - (Windows x 15 sq ft)
Gallons = ceil((Area x Coats) / Coverage per gallon)
Primer gallons = ceil(Area / 300 sq ft). Primer covers less due to absorption on bare surfaces.
How much paint do I need per coat?
One gallon covers 350 to 400 sq ft on smooth drywall, or 250 to 300 sq ft on textured walls. A standard 12x12 room needs about 1 gallon per coat.
Do I really need primer?
Yes for new drywall, dramatic color changes, and stain-blocking. A primer like Zinsser Bulls Eye 1-2-3 ($28/gal) saves you from needing a third coat.
Is premium paint worth the extra cost?
Usually yes. Benjamin Moore Regal ($55/gal) covers in 1 coat vs 2 coats with economy paint, and lasts 8 to 10 years vs 3 to 5.
How much does it cost to hire a painter?
Professional interior painting averages $2-6/sq ft. A single 12x12 room costs $400-800. Whole-house interiors run $3,000-9,000.
What's the best paint sheen for each room?
Flat for ceilings, eggshell for living rooms, satin for hallways and kids' rooms, semi-gloss for kitchens, bathrooms, and trim.
How long should I wait between coats?
Latex needs 2 to 4 hours at 70°F. Below 50°F or above 85% humidity, wait 6 to 8 hours. Oil-based requires 24 hours.
Should I use a brush or roller?
Use a 9" roller with 3/8" nap for smooth walls and a 2.5" angled brush for edges. For textured walls, use a 3/4" nap roller.
How do I estimate prep work costs?
Basic prep adds $0.50/sq ft. Moderate prep (patching, caulking, priming) adds $1.00-1.50/sq ft. Heavy prep adds $2.00-4.00/sq ft.
430 sq ft paintable | 3 gal Behr Ultra | $105 paint + $56 supplies = $161 total
Tip: A weekend project. Boxing all paint into one bucket eliminates color variation between gallons.
4,200 sq ft walls | 12 gal Duration + 4 gal primer | $17,752 total installed
Tip: Professional labor at $3.50/sq ft is 83% of the total cost. Typical timeline: 5-7 business days.
30 doors + frames | 2 gal BM Advance + 1 gal primer | $138 DIY materials
Tip: Cabinet painting is the most labor-intensive paint project. Pro cost: $3,000-5,000 for a typical kitchen.
Skipping Primer to Save Money
Without primer on new drywall, you'll need 3 coats instead of 2. A $28/gal primer saves $40-55 in extra paint and prevents stain bleed-through.
Buying the Cheapest Paint Available
Economy paint ($25-30/gal) needs 2 to 3 coats and fades in 3 to 5 years. Premium ($50-65/gal) covers in 1 to 2 coats and lasts 8 to 10 years.
Not Accounting for Texture and Porosity
Textured walls and bare wood absorb 20 to 30% more paint. Increase your estimate by 25% for orange peel or knockdown texture.
Painting in Bad Weather Conditions
Latex paint below 50°F or above 85°F won't bond properly. High humidity (above 85%) causes drips and extended dry times.
Forgetting to Factor in Prep Costs
Budget $50-100 per room for spackle, caulk, sandpaper, and TSP. Skipping prep leads to peeling within 6 to 12 months.
Underestimating the Perimeter Measurement
Measure each wall individually. Closets, bump-outs, and odd angles in a 12x14 room add 4+ feet beyond a simple rectangle estimate.
Important Disclaimer
These estimates are for planning purposes only. Actual costs vary by location, material availability, and project complexity. Always get at least 3 local quotes. This calculator does not replace professional advice.