How it works
Gallons = ((room perimeter × height − openings) × coats × texture allowance) ÷ coverage.
Input definitions
- Room length (ft)
- Enter the value in the labeled unit.
- Room width (ft)
- Enter the value in the labeled unit.
- Wall height (ft)
- Enter the value in the labeled unit.
- Door and window area (ft²)
- Enter the value in the labeled unit.
- Number of coats
- Enter the value in the labeled unit.
- Coverage per gallon (ft²)
- Enter the value in the labeled unit.
- Extra absorption allowance (%)
- Enter the value in the labeled unit.
A worked example
- Room length (ft)
- 14
- Room width (ft)
- 12
- Wall height (ft)
- 8
- Door and window area (ft²)
- 45
- Number of coats
- 2
- Coverage per gallon (ft²)
- 350
- Extra absorption allowance (%)
- 10
Assumptions & limits
Uses only the values entered. Rates are illustrative inputs, not live quotes, legal rules or personalised advice. Check provider terms, local requirements and measurements before acting.
Sources & review
Maintained by AnsRio. Methods and examples use automated checks; this does not imply independent professional certification.
Method updated 2026-10-19. Content checked against the stated method and examples. Our verification approach.
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Common questions
Why include a texture allowance?
Rough or porous walls can consume more paint than the label coverage. Use a tested allowance for your surface.
How does Room paint with doors and windows calculate the result?
Gallons = ((room perimeter × height − openings) × coats × texture allowance) ÷ coverage.
What should I verify before using Room paint with doors and windows?
Uses only the values entered. Rates are illustrative inputs, not live quotes, legal rules or personalised advice. Check provider terms, local requirements and measurements before acting.