How to use this calculator
Enter the net wall area and coverage for one US gallon applied as one coat. Then set the intended coat count, extra allowance and container size. The tool estimates liquid usage and rounds the order to whole containers.
The calculation explained
Gallons = measured area × coats × (1 + allowance ÷ 100) ÷ product-rated area covered per gallon per coat. Containers = round up(gallons ÷ gallons per container).
Check these details before ordering
- Check if your product data reports a diluted or an undiluted yield.
- Test coverage on your actual surface, especially if the wall is porous.
- Keep gallon and litre conversions separate from changes in surface coverage.
Frequently asked questions
How many coats of limewash should I enter?
Use your chosen product’s instructions and desired finish. The two-coat starting value is an example, not a universal recommendation.
Why does this tool ask for square feet per gallon?
Manufacturers publish different coverage rates. Entering your own rated area per gallon is more reliable than relying on a universal default.
Does the calculation include primer?
No. Estimate compatible primer and sealer separately where the manufacturer specifies them.
Read the related guide
For more context, see How to Read Paint and Decorative Plaster Coverage Rates. It explains practical assumptions that a calculator cannot confirm for your individual project.