Quick answer
Plan exterior wall paint using measured facade area, openings, coats and real product coverage. Use the working RenoMetric calculator below for the actual estimate, then use this page to check assumptions, package rounding and project-specific considerations.
Open the working Paint calculator
Formula
Worked planning example
A 40 ft wide wall that averages 18 ft high has about 720 ft² gross area before subtracting major windows and doors.
Common uses
- Siding
- Stucco
- Exterior masonry
- Garage exteriors
How to get a better estimate
Measure the actual project rather than relying on listing dimensions. For irregular spaces, split the surface into simple measurable sections and add the results. Use the exact product label for package coverage, yield, density or square-foot coverage whenever it is available.
Keep waste and package rounding as separate steps. Waste covers cuts, breakage, pattern matching and unavoidable offcuts. Package rounding reflects the fact that many materials are sold only in complete bags, boxes, bundles or cans.
Before you buy: this page is a planning guide, not a contractor quotation or structural design. Verify final quantities with the product manufacturer, supplier or installer when project conditions could materially change the result.
Exterior Paint Calculator FAQ
Does rough siding use more paint?
It can. Rough, porous or heavily textured surfaces often reduce practical coverage compared with the label maximum.
Should I include primer?
Primer should be estimated separately when the substrate, repair work or paint system requires it.
How do I handle gable ends?
Measure rectangular sections and triangular gables separately, then add their areas.