Paintable surface
wall_area + trim_areaCombines the measured surfaces that receive the selected coating.
Inputs
Adjust the project details to update the estimate.
Planning estimates use standard formulas. Verify quantities with your supplier before ordering.
Estimate
A paint order that matches the surfaces.
Paint gallons
Rounded-up quantity for the chosen coverage and number of coats.
12 gallons
Wall paint
The main facade quantity before detail surfaces are added.
$420–$900
Paintable surface: wall_area + trim_area
Estimates use standard planning formulas. Verify quantities with your supplier or contractor before ordering.
See your project with AIPaint quantity planning
Exterior Paint Calculator
Estimate how much exterior paint to buy by separating wall faces from trim and doors. Change coverage or coats to match the product on your shelf.
Free to use Instant results Planning estimate
How to calculate exterior paint
Paint follows paintable surface area, not the square footage of the house. Measure walls, subtract large openings, and estimate trim, doors, shutters, and masonry details separately.
Divide the coated area by the coverage printed on the can, then multiply by coats. Rough siding, porous masonry, dramatic color changes, and weathered surfaces can lower real-world coverage.
Keep a small reserve from the same batch for touch-ups. Preparation, caulking, primer, access, and repairs can matter more to the final job than the gallon count alone.
Formulas used
Gallons
paintable_area × coats ÷ coverageAccounts for repeated coats and the product's square-foot coverage.
Purchase quantity
ceil(gallons)Rounds up so the project does not run short during application.
Frequently asked questions
What to know before you order.
Should windows and doors be subtracted?
Subtract large openings from the wall area, then add the trim or door surfaces that will actually receive paint.
How many coats should an exterior need?
Two coats are common for many repaints, but bare material, color changes, and the product label determine the real requirement.
Is labor included in the result?
No. Labor depends on preparation, height, access, repairs, masking, and the number of coats.
See it before you build it
Try AI home design Test the color before opening a can
Upload an exterior photo and explore paint, trim, and material directions with AI before buying samples.