Skip to content
CostToUpgrade
CalculatorsCost GuidesCost DataMethodology Search Browse calculators
Painting

Exterior Paint Calculator

Estimate paint for the outside of a house. Exterior siding is rougher and thirstier than interior drywall, so a gallon covers 200–300 ft² per coat instead of the 350 ft² on the label. Enter your wall area, subtract the windows and doors, pick your siding texture, and get gallons, primer, and paint cost.

Reviewed by The CostToUpgrade Estimating Desk Last reviewed How we estimate

Your project

Dimensions

Perimeter × height, plus gable triangles (½ × base × height for each gable).

Count 15 ft² per window and 21 ft² per door. Most homes land at 150–250 ft².

Material

The rougher the surface, the more paint it drinks per square foot.

Two coats is the manufacturer-spec default for a full repaint; one coat is maintenance only.

Pricing

100% acrylic exterior paint typically runs $45–$70 per gallon.

Estimate

13gal

Paint needed · Rounded up to the next half gallon

Net paintable area
1,600ft²
Primer (one coat)
6.5gal
Estimated paint cost
$676.00

Estimates are guidance only and exclude tax, labor, and site conditions unless stated. Confirm with a local pro.

How it's calculated

No black boxes — here is the exact math behind your estimate, so you can check it or adapt it for your own quote.

  1. 1Net area (ft²) = wall area − windows and doors
  2. 2Coverage = 300 (smooth), 250 (lap siding), or 200 (rough stucco) ft² per gallon per coat
  3. 3Gallons = net area × coats ÷ coverage, rounded up to the next half gallon
  4. 4Primer gallons = net area ÷ coverage, rounded up to the next half gallon
  5. 5Cost = gallons × price per gallon

Worked example

A two-story house with 1,800 ft² of lap siding, 200 ft² of windows and doors, painted with two coats.

Inputs

Total wall area
1800 ft²
Windows & doors
200 ft²
Siding texture
250
Coats
2
Price per gallon
52 $/gal

Result

Paint needed
13 gal
Net paintable area
1,600 ft²
Primer (one coat)
6.5 gal
Estimated paint cost
$676.00

Tools & materials for this project

As an Amazon Associate we may earn from qualifying purchases, at no extra cost to you.

  • Airless paint sprayer Covers siding far faster than a roller — back-brush to work paint into the grain.
    View on Amazon
  • Exterior paintable caulk Seal siding joints and trim gaps before the first coat goes on.
    View on Amazon
Get real quotes

Compare local pros for exterior house paint

An estimate gets you a budget. A few competing quotes get you the real price. Tell us about the job and we'll help you find vetted contractors nearby.

Get matched

Exterior Paint cost by state

The calculator does the quantity math exactly. What it can't know is what a fair unit price looks like where you live — exterior house paint runs 61% more in the priciest US market than the cheapest.

Exterior Paint cost in all 50 states + DC US average $52 per gallon of exterior paint · regional averages, full ranked table, and typical project totals.

Frequently asked questions

When is a second coat of exterior paint non-negotiable?
Always on bare wood, new primer, patched areas, chalky weathered siding, and any real color change — light over dark hides only after two coats, and strong reds and yellows can need three. One coat lays down roughly 1.5–2 mils of dry film; manufacturers spec 3–4 mils total to hit their stated durability, and most exterior warranties assume two coats over the correct primer. A single coat is honest maintenance work only when you are recoating a sound existing film in essentially the same color and sheen.
Why does exterior paint cover less than the can claims?
Label spread rates of 350–400 ft² per gallon are measured on a smooth, sealed, non-porous test panel. Real siding is not that. Lap siding adds butt joints and drip edges, shakes and rough-sawn cedar soak paint into the grain, and rough stucco or split-face block can drop you to 150–200 ft² per gallon. Add what stays in the tray, the roller cover, and the brush, plus 20–30% lost to overspray if you use an airless in any breeze. Planning at 250 ft² for lap siding and 200 ft² for stucco is realistic, not pessimistic.
What temperature and dew point can I paint in?
Most 100% acrylic exterior paints are labeled for a 50°F minimum air and surface temperature, with low-temp formulas rated to about 35°F; oil-based alkyds usually want 45–50°F. The temperature has to stay above that minimum for several hours after application while the film coalesces. Keep the surface at least 5°F above the dew point so condensation does not land on wet paint, and stop a couple of hours before evening dew forms. Avoid painting a wall in direct sun above roughly 90°F surface temperature — the film skins over before it flows out and lap marks lock in.
How do I estimate trim, fascia, and doors?
Figure trim by the linear foot and keep it out of the wall tally, because it usually gets a different product and sheen. Multiply the run by the board width: 6-inch fascia is 0.5 ft² per linear foot, 4-inch casing is 0.33 ft². As a shortcut, a gallon of trim enamel covers roughly 350–400 linear feet of 4–6 inch trim in one coat. Doors are about 21 ft² per side, so one gallon handles several. On a typical house, budget one to two gallons of trim paint on top of the body paint this calculator returns.
How much paint does a 2,000 sq ft house need?
Floor area is not paint area. A two-story 2,000 ft² home usually has 1,700–2,200 ft² of exterior wall once gables are included. Take 1,800 ft² of wall, subtract about 200 ft² of windows and doors, and you have 1,600 ft² net. On lap siding at 250 ft² per gallon that is 6.5 gallons per coat, so 13 gallons for two coats — roughly $676 in paint at $52 a gallon, plus primer for bare spots. Buy it in one purchase so every gallon comes from the same tint batch.

Related calculators

Painting

Paint Calculator

Open calculator

Painting

Deck Stain Calculator

Open calculator

Flooring

Square Footage Calculator

Open calculator

Painting

Garage Floor Epoxy Calculator

Open calculator