How to estimate paint for a house exterior
The outside of a house is a box with triangles on top. Find the area of the walls, add the gables, take off the windows and doors, then divide by what a gallon covers on your siding. Here it is with the calculator's starting house: 40 x 30 ft, two stories, two gables at a 6/12 pitch, 12 windows, 2 doors, vinyl siding.
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1
Walls: perimeter times height
(40 + 30) x 2 = 140 ft around. At 18 ft from the ground to the eaves, that is 2,520 sq ft.
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2
Gables: half of width times rise
A 6/12 roof rises 6 inches per foot. Over half of a 30 ft width, that is 7.5 ft. Each gable is ½ x 30 x 7.5 = 112.5 sq ft, so two add 225 sq ft.
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3
Subtract windows and doors
About 15 sq ft per window and 21 sq ft per door. 2,745 − 180 − 42 = 2,523 sq ft of siding.
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4
Multiply by coats, divide by coverage
2,523 x 2 coats ÷ 350 sq ft per gallon = 14.4 gallons. Three 5-gallon buckets cover it with a little left for touch-ups.
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5
Add the trim
Fascia and soffits, rake boards, corner boards and window and door casings come to about 375 sq ft here. Two coats take 2.1 gallons: 2 gallons and a quart.
With a quart for the doors, caulk, rollers, prep tools and a day's pressure-washer rental, the DIY total is about $1,080.
Coverage by siding type
Exterior paint labels usually promise 250 to 400 sq ft per gallon. Where you land in that range depends on how rough and thirsty the surface is.
| Siding | Sq ft per gallon | Notes |
|---|---|---|
| Vinyl or aluminum | about 350 | Use a vinyl-safe color no darker than the original |
| Fiber cement | about 325 | Takes paint well; factory-primed boards need no primer |
| Wood lap or shingles | about 300 | Weathered and rough-sawn wood drink more |
| Brick | about 225 | Porous; the first coat on bare brick soaks in |
| Stucco | about 200 | Rough textures need a thick-nap roller or a sprayer |
Spraying uses more paint than rolling, often 20 to 30% more because of overspray. If you plan to spray, raise your gallon count or choose the next texture down in the calculator.
Paint for common house sizes
Vinyl siding, two coats, two 6/12 gables, 12 windows and 2 doors. Tap a house to load it.
| House | Siding area | Siding paint | Trim |
|---|---|---|---|
| 40 x 25, 1 story | 1,104 sq ft | 6.3 gal | 1.9 gal |
| 50 x 30, 1 story | 1,443 sq ft | 8.2 gal | 2.2 gal |
| 60 x 30, 1 story | 1,623 sq ft | 9.3 gal | 2.3 gal |
| 40 x 25, 2 stories | 2,274 sq ft | 13.0 gal | 2.0 gal |
| 40 x 30, 2 stories | 2,523 sq ft | 14.4 gal | 2.1 gal |
| 50 x 35, 2 stories | 3,144 sq ft | 18.0 gal | 2.4 gal |
Prep decides how long the paint lasts
Paint fails at the surface, not in the can. Pros spend as long on prep as on painting:
- Wash first. A pressure washer on a low setting, or a garden sprayer with cleaner and a brush, removes dirt and mildew. Let wood dry for a couple of days.
- Scrape and sand loose paint, then spot-prime bare wood. Paint over loose paint peels within a season.
- Caulk the gaps around windows, doors and trim joints with paintable exterior caulk. Do not caulk the bottom edges of lap siding; it needs to drain.
- Rub the old paint. If chalk comes off on your hand, wash it off and use a primer made for chalky surfaces.
- Watch the weather. Check the can for the minimum temperature, avoid painting in direct midday sun, and stop early enough that dew won't land on wet paint.
What it costs: DIY vs hiring a painter
Paint is the smaller part of a pro's bill. Painters usually charge $1.50 to $4 per square foot of paintable surface, and the national average job is a little over $3,000. Labor is most of that. Prices climb with each extra story, with steep or hard-to-reach gables and with heavy prep. A good exterior paint costs about $35 to $50 a gallon at home centers and $65 to $95 at paint stores, so even premium paint rarely adds more than a few hundred dollars.
A one-story house is a fair DIY project over a few weekends. Two stories means long ladders or rented scaffolding, and the risk goes up with the height. If you are not comfortable working 20 feet up, hire the high walls and do the low ones yourself. Keep ladders well clear of the power line that feeds the house.
Older homes: if the house was built before 1978, the old paint may contain lead. Sanding or scraping it spreads lead dust. Test first, and know that the EPA requires contractors to be lead-safe certified to disturb more than 20 sq ft of painted exterior on these homes.
Common questions
How much paint do I need for the outside of a 2,000 square foot house?
A two-story house with a 2,000 square foot floor plan, about 40 by 25 feet, has roughly 2,200 to 2,400 square feet of siding after windows and doors. Two coats on vinyl siding take about 13 gallons, plus about 2 gallons for the trim.
How many square feet does a gallon of exterior paint cover?
Most exterior paint covers 250 to 400 square feet per gallon. Smooth vinyl and fiber cement land near the top of that range. Rough stucco, bare wood and brick soak up more, often 200 to 250 square feet per gallon.
Do I need two coats of exterior paint?
Two coats are the norm for a color change, bare or weathered wood, stucco and masonry, and they last longer in sun and rain. One coat can work when you repaint the same color over sound paint.
How much does it cost to paint the outside of a house?
Hiring a painter usually costs $1.50 to $4 per square foot of paintable surface, and the national average is a little over $3,000. Doing it yourself costs mostly paint and supplies, often $600 to $1,500 for an average house.
Do I need to prime before painting exterior siding?
Prime bare wood, new stucco or masonry, chalky or patched areas and any big color change. Sound, clean paint usually needs no primer, and many exterior paints are self-priming over previously painted surfaces.
When is the best time to paint a house exterior?
Pick dry days with mild temperatures, usually late spring or early fall. Check the can for the minimum temperature, avoid painting in direct midday sun, and leave time for the paint to dry before dew or rain.
Sources and assumptions
Prices are US averages checked in October 2026 and vary by region and store. The siding paint price can be edited in the calculator.
- Coverage: Behr Ultra Exterior and Behr masonry, stucco and brick paint list 250 to 400 sq ft per gallon depending on substrate porosity. The per-siding values (350, 325, 300, 225, 200) are our estimates within and below that range; rough stucco and bare brick often fall under 250. As a cross-check, the estimating software maker Vertigraph uses 175 to 225 sq ft per gallon for stucco or concrete block and 250 to 300 for bare wood (checked November 2026).
- Paint prices: Home Depot, Behr Ultra exterior (about $35 to $50 per gallon) and Sherwin-Williams, Duration Exterior (about $78 to $82 per gallon on sale). Default $50 for siding and $55 for trim enamel; a 5-gallon bucket is priced like 4.4 single gallons.
- Painter cost: Angi, cost to paint a house exterior ($1.50 to $4 per sq ft, average about $3,177). Fixr reports higher per-siding ranges, so treat the pro range as a starting point for quotes.
- Lead paint: EPA Renovation, Repair and Painting Program.
- Trim area is estimated as 1.5 sq ft per foot of perimeter (fascia and soffit), 0.67 sq ft per foot of gable rake, 5 sq ft per window, 6 sq ft per door and four corner boards 8 inches wide. Openings: 15 sq ft per window, 21 sq ft per door. Primer covers 300 sq ft per gallon (200 on stucco and brick) at $35.
- Supplies at typical prices: exterior caulk $8 a tube (one per 30 ft of joints), door enamel $24 a quart, roller and brush kit $45, scrapers and brushes $20, drop cloths and plastic $30, pressure washer rental $90 a day. DIY time assumes about 150 sq ft per hour per coat plus prep.