How to use this calculator
Enter the surface area once. Set primer and sealer coverage independently, based on each chosen product’s manufacturer documentation. Choose the number of coats, can sizes and prices. Enter zero coats for any product that your system does not require.
The calculation explained
Each liquid’s gallons = surface area × its coat count × (1 + extra allowance ÷ 100) ÷ its rated area per gallon per coat. Its purchase cans = round up(gallons ÷ can size); zero coats produces zero cans.
Check these details before ordering
- Only pair primers, plasters and sealers approved for use together.
- Read the manufacturer’s guidance for drying and recoat conditions.
- Avoid ordering a second product solely because the calculator offers that input.
Frequently asked questions
Do all decorative finishes need both primer and sealer?
No. Requirements vary by product and intended use. Set a product’s coat count to zero if the specification does not require it.
Can I use different container sizes?
Yes. Enter a separate container size for primer and sealer.
Does this estimate drying time?
No. Consult each product’s technical data sheet for application conditions and recoat intervals.
Read the related guide
For more context, see Planning Decorative Finishes for Bathrooms and Other Wet Areas. It explains practical assumptions that a calculator cannot confirm for your individual project.