What does this tool do?
Primer coverage changes with how porous the surface is. This calculator applies a surface factor to the area, multiplies by the number of coats and divides by the coverage printed on the product.
The Formula
Litres = Area × Surface factor × Coats ÷ Coverage (sq ft per litre)Frequently Asked Questions
How many coats of primer?
One coat is normal on drywall and previously painted walls; bare wood and masonry may need two.
Does primer coverage differ by surface?
Yes. Porous new drywall and masonry absorb more, while a sound painted surface needs less.