Exterior Paint Calculator
Estimate exterior paint coverage, full containers, purchased capacity, material cost and labor allowance from wall perimeter, height, openings and coat count.
Default project preview
7 containers
Net wall area
1,220 ft²
Total coat area
2,440 ft²-coats
Purchased capacity
2,800 ft²-coats
Material cost
$336.00
Calculator
Build the material order
Your order will appear here
Enter the project details and calculate a rounded material estimate.
Input and output guide
What each value means
The labels and units below are part of this calculator’s visible methodology. Replace every default with measurements or product data from the actual project.
Exterior wall perimeter
Enter this project assumption in ft. The current imperial default is 160 ft.
Average wall height
Enter this project assumption in ft. The current imperial default is 9 ft.
Doors and windows
Enter this project assumption in ft². The current imperial default is 220 ft². Minimum: 0.
Paint coats
Enter this project assumption in a unitless value. The current imperial default is 2. Minimum: 1.
Extra allowance
Enter this project assumption in %. The current imperial default is 10 %. Minimum: 0. Maximum: 30.
Coverage per container per coat
Enter this project assumption in ft². The current imperial default is 400 ft².
Price per container
Enter this project assumption in a unitless value. The current imperial default is 48. Minimum: 0.
Labor rate
Enter this project assumption in per ft². The current imperial default is 1.5 per ft². Minimum: 0.
How to read the outputs
Net wall area
openings deducted. Default preview: 1,220 ft².
Total coat area
before allowance. Default preview: 2,440 ft²-coats.
Purchased capacity
full containers. Default preview: 2,800 ft²-coats.
Material cost
paint containers. Default preview: $336.00.
Labor allowance
entered wall-area rate. Default preview: $1,830.00.
Estimated project cost
paint plus labor. Default preview: $2,166.00.
Methodology
Transparent calculation
BuildMeter converts every input to a consistent internal unit, applies the selected allowance, and rounds products up to whole purchasable units.
Net wall area = perimeter × height − openings. Coat area multiplies by the number of coats, then allowance is applied before full containers are rounded up.
Reviewed project guidance
How to use this estimate in a real project
Last reviewed: July 29, 2026
This calculator estimates exterior paint and primer from wall, trim, opening and coat inputs. It supports quantity planning but does not determine coating compatibility, surface preparation or safe access.
Calculation steps
- 1Calculate gross wall area by elevation.
- 2Subtract large openings and add trim, soffit or other separately coated surfaces.
- 3Multiply by coat count.
- 4Use product coverage for the substrate texture and round to full containers.
Worked numerical example
A house with 2,000 ft² of net siding, two finish coats and 350 ft²/gallon coverage needs 11.43 gallons before allowance. With 10% allowance, purchase at least 13 gallons in available containers.
Purchasing and rounding
Primer and finish paint should be calculated separately when their coverage differs. Keep enough finish paint from the same tint batch for touch-up.
Interpret the result
Rough masonry, stucco and weathered wood can consume much more paint than smooth siding. Coverage should reflect the actual substrate, not a universal value.
Page-specific assumptions
- Measured elevations represent all coated surfaces.
- Coverage matches application method and texture.
- Coat count is entered separately for primer and finish where needed.
- Overspray is included in allowance.
Common mistakes
- Using floor area instead of wall area.
- Subtracting every small opening.
- Ignoring gables and soffits.
- Painting incompatible or damp surfaces.
Primary and technical references
BuildMeter provides planning estimates, not engineering, architectural, electrical, mechanical, plumbing, permit or code approval. Review the methodology and verify final decisions with product documentation and qualified professionals.
BuildMeter Guides
Understand the measurements and assumptions
Use these visible reference guides before changing project inputs or planning allowances.
FAQ
Exterior Paint Calculator questions
Does rough siding use more paint?+
Yes. Textured or porous surfaces can reduce coverage significantly.
Should primer be counted as a paint coat?+
Primer is usually estimated separately because its coverage and price can differ.
Does this include soffits and trim?+
No. Add those measured areas or estimate them separately.