Paint Cost Calculator
Estimate what it costs to paint a room: gallons of paint and primer to buy, material cost, optional pro labor per square foot and the cost per square foot of wall.
By CalcBuilt Editorial TeamUpdated September 9, 2026Formulas checked against manufacturer specs, see how we calculate.
Results
- Total cost to paint
- $90
- Materials only, DIY for 2 coats on 334 sq ft of wall
- Paint to buy
- 2 gallons
- $90 at $45.00 per gallon can; 1.91 gal needed for 2 coats
- Cost per square foot
- $0.27 per sq ft
- Total cost / 334 sq ft of wall
Paint Cost formula
Area = 2 x (Length + Width) x Height - (Doors x 20) - (Windows x 15) (+ Length x Width if the ceiling is included)
Gallons to buy = round up (Area x Coats / Coverage per gallon)
Paint cost = Gallons x price per gallon; Primer cost = round up (Area / 300) x $30
Total = Paint + Primer + (Labor rate x Area); Cost per sq ft = Total / AreaWorked example
A 14 x 16 ft living room with 9 ft ceilings, two doors and three windows, painted with $40 per gallon paint: 2 x 30 x 9 = 540 sq ft, minus 40 for doors and 45 for windows = 455 sq ft of wall. Two coats at 350 sq ft per gallon: 455 x 2 / 350 = 2.6 gallons, so buy 3 gallons for 3 x $40 = $120. One coat of primer: 455 / 300 = 1.52, so 2 gallons at $30 = $60. DIY materials come to $180, or $0.40 per sq ft.
Hiring a painter at $3 per sq ft adds 455 x $3 = $1,365 in labor, for a total of $1,545, or $3.40 per sq ft of wall.
Quick reference
| Room size | Wall area | Gallons to buy | DIY paint cost | With pro labor at $3/sq ft |
|---|---|---|---|---|
| 10 x 10 ft | 270 sq ft | 2 | $90 | $900 |
| 12 x 12 ft | 334 sq ft | 2 | $90 | $1,092 |
| 12 x 15 ft | 382 sq ft | 3 | $135 | $1,281 |
| 15 x 20 ft | 510 sq ft | 3 | $135 | $1,665 |
| 20 x 20 ft | 590 sq ft | 4 | $180 | $1,950 |
How to estimate the cost of painting a room
Start with the wall area: perimeter times ceiling height, less about 20 sq ft per door and 15 per window. Multiply by coats, divide by the coverage on the can, and round up to whole gallons. Over 3 gallons buy a 5 gallon bucket: one batch and cheaper per gallon; box separate gallons together before the first coat. Add a gallon of primer per 300 sq ft where needed: PVA on bare drywall and spot priming on patches so they do not flash. A gray-tinted primer under deep reds and yellows keeps the job at two coats.
A first-room supply kit (9 in roller frame and two covers, a 2-1/2 in angled sash brush, tape, tray and drop cloth) typically runs $40 to $60 in 2026. Ceiling paint is a separate dead-flat product. Trim, doors and casings take about a quart per 100 sq ft, each door side counting as about 20 sq ft. None of that is in this estimate.
DIY vs hiring a painter
Doing it yourself saves most of the cost. Materials for a bedroom run under $150; a pro quote for the same room, walls only, typically comes back at $600 to $1,000 in 2026. Painters quote by the room, but the number underneath is $45 to $75 per painter-hour times 6 to 10 hours for a 12 x 12 bedroom. About half of those hours are prep: furniture, nail holes, caulk, sanding, tape and floor protection. Cut lines, stairwells and ceilings over 9 ft that need staging push the hours up.
When you get bids, ask whether paint is included, how many coats, and whether ceilings and trim are extra. Ceilings typically add 30 to 50 percent to a walls-only quote and doors run $75 to $150 each, both sides. Walk the room with the painter first; cracks, water stains and popcorn found on the day become change orders. If a quote includes paint, set the paint price here to 0 and enter the rate as labor.
What this calculator leaves out
The result is wall paint, optional primer at $30 per gallon and labor on the same area. It leaves out trim and door paint, sample quarts, the supply kit, and repairs such as skim coating or popcorn removal. Ceilings are charged here at the wall rate; pros charge more overhead. Custom-tinted gallons are not returnable, so buy a sample before the bucket.
Mistakes that cost money
- Comparing a per-room quote to a per-square-foot quote without asking what is in it; ceilings, trim, paint and repairs are extras on some bids.
- Skipping the walk-through with the painter; cracks, nail holes and popcorn found on the day are billed as change orders at hourly rates.
- Paint-and-primer in one over new drywall flashes at every joint; bare board needs a PVA primer coat that is not in the paint price.
- Four single gallons instead of a 5 gallon bucket cost more per gallon and come from different batches; the shade shift shows where cans changed.
- Entering a painter's rate that includes paint while leaving the paint price at $45 counts the paint twice; set the price to 0.
- Deep red or yellow over white takes four coats without a gray-tinted primer, which doubles both the paint and the labor hours.
Key facts
- Labor is the largest share of a professional paint job; paint is usually 15 to 25% of the total, so a $90 material estimate typically comes back as a $600 to $1,000 quote for one bedroom, walls only, in 2026.
- Professional painters typically charge $2 to $6 per sq ft of wall in 2026, built from $45 to $75 per painter-hour; a 12 x 12 bedroom is 6 to 10 labor hours and about half of that is prep.
- Mid-grade interior paint is typically $35 to $60 per gallon in 2026 and top lines $80 to $100; paint-and-primer on the label is a marketing term, not a substitute for primer on bare drywall.
- One gallon covers about 350 to 400 sq ft per coat, so a 12 x 12 ft room takes about 2 gallons for two coats on the walls.
- Primer runs about $20 to $40 per gallon and covers 250 to 300 sq ft; bare drywall needs PVA, water stains need a stain blocker, and deep colors need a gray-tinted primer.
Frequently asked questions
How much does it cost to paint a 12x12 room?
About $90 in paint for two coats on the walls at $45 per gallon if you do it yourself. A pro typically quotes $600 to $1,000 for the walls in 2026, which is $2 to $3 per sq ft of the room's 334 sq ft. Adding the ceiling, trim and wall repairs pushes it toward $1,500 to $2,000.
How much do painters charge per square foot?
Typically $2 to $6 per sq ft of wall for interior work in 2026, usually including paint and basic prep. Ceilings, trim, repairs and ceilings over 9 ft are priced on top. Most painters quote by the room; the per-square-foot number is how they build it.
How much paint do I need for a 12x12 room?
334 sq ft of wall x 2 coats / 350 sq ft per gallon is 1.91 gallons, so buy 2 gallons. Add about 1 gallon of ceiling paint for the 144 sq ft ceiling.
Why is the quote $800 when the paint costs $90?
Because the room is 6 to 10 labor hours at $45 to $75 an hour. Half of that is prep you do not see in the finished wall: filling, caulking, sanding, taping and cleanup. The painter also carries insurance, a truck and a helper, and warranties the job.
Sources and references
- Paint calculator: paint and primer coverage per gallon (Sherwin-Williams)
- KILZ 2 All-Purpose Primer product page (KILZ)
- Painters, Construction and Maintenance, Occupational Outlook Handbook (U.S. Bureau of Labor Statistics)
Next steps for this project
The usual order for a paint & walls project. See all paint & walls calculators.
Embed this calculator
Results are estimates based on standard formulas and typical product specifications. Confirm quantities with your supplier and local code before ordering.