How to use this calculator
- Add every exterior wall section.
- Enter door and window counts and representative opening areas.
- Choose the number of coats.
- Enter the selected product’s coverage rate and calculate.
How the calculation works
Exterior wall sections are combined into gross area. Openings are deducted, coats are applied to the remaining area, and the coated area is divided by the coverage you enter.
Formula
Gross exterior area = Σ(wall width × height) Paintable area = gross area − entered openings Paint quantity = paintable area × coats ÷ coverage
Worked example
Four exterior wall sections totaling 800 square feet, less 80 square feet of entered doors and windows, leave 720 square feet. Two coats at 300 square feet per gallon require 4.8 gallons.
Project considerations
- The coverage default is an editable example, not a universal exterior-paint claim.
- Surface material, porosity, condition, preparation, and application method affect actual coverage.
- Gables, trim, soffits, and irregular features should be measured separately where applicable.
Frequently asked questions
Does this select an exterior paint system?
No. It only estimates quantity from the geometry, openings, coats, and coverage entered.
Does every exterior need two coats?
No. Coat count is editable and should follow the selected product and project requirements.