The Exterior House Painting Cost Calculator estimates the cost to paint the outside of a house. From the footprint (length × width), wall height to the eaves and the gable ends, it calculates the paintable wall area, subtracts doors and windows, works out the gallons needed, and adds labor (including prep) plus a lump sum for trim, gutters and extras.
Exterior House Painting Cost Calculator
Estimate the cost to paint a house exterior from its footprint and height, with paint, labour and trim.
The paint price and labor rate are examples — replace them with local quotes.
Formula
Walls = 2(L + W) × H + gables × ½ × W × gable height − openings
Gallons = ⌈walls × coats ÷ coverage⌉
Total = gallons × price + walls × labor rate + trim & extras
Where L, W = house length and width, H = wall height to the eaves; each gable is a triangle with its base on the house width.
How the Calculation Works
Step 1: Perimeter × wall height gives the rectangular wall area.
Step 2: Add the triangular gable ends.
Step 3: Subtract doors and windows.
Step 4: Paint = area × coats ÷ coverage; labor is per ft² of wall.
Example Calculation
Given (example prices): 50 × 30 ft house, 18 ft to the eaves, 2 gables 6 ft high, 250 ft² of openings, 2 coats, 300 ft²/gal, $55/gal, $2.50/ft² labor, $800 trim and extras
- Walls = 160 × 18 = 2,880 ft²
- Gables = 2 × ½ × 30 × 6 = 180 ft²
- Paintable = 2,880 + 180 − 250 = 2,810 ft²
- Gallons = 5,620 ÷ 300 = 18.7 → 19 → $1,045
- Labor = 2,810 × 2.50 = $7,025
- Total = 1,045 + 7,025 + 800 = $8,870
What Affects Exterior Painting Cost
- Siding type: rough or textured surfaces (stucco, shingles) absorb more paint than smooth siding.
- Stories and access — ladders, scaffolding or lifts.
- Prep: power washing, scraping, repairs, caulking and primer.
- Trim, shutters, gutters and doors, often priced separately.
- Older homes may have lead paint; follow lead-safe practices where required.
Frequently Asked Questions
How much does it cost to paint a house exterior?
Paint for the wall area plus labor per ft² plus trim; the calculator adds your local prices.
How do I calculate the exterior wall area of a house?
Perimeter × wall height, plus gable triangles, minus openings.
How many gallons of paint for a house exterior?
Paintable area × coats ÷ coverage; the example house needs 19 gallons.
How do I measure a gable?
Height from the eave line to the peak; the base is the house width.
Is exterior paint coverage lower than interior?
It can be on rough surfaces; use the coverage on the can for your surface.