Last checked
March 28, 2026
We checked the calculator logic, page links, and support content used on this page.
Decorating Estimating
Estimate primer for new plaster before you open the first tin
New plaster surfaces can absorb far more than a smooth repaint, so this page focuses on a more cautious primer estimate.
How to use it
Use it as a planning estimate
Use this guide to build a rough material estimate, then confirm the final order against product data and site conditions.
Why trust it
See how the site is maintained
Read the calculator methodology and editorial policy for the standards behind these pages.
Use the calculator first
The quickest path is to start with Primer Calculator, then use this guide to sense-check the result and decide what to buy next.
Why this page exists
Best for products sold by tin, tub, bag, roll, sheet, pack, or board, where the real question is how many whole units the job needs. On this page, that usually means turning simple measurements into a more practical material order.
Core assumption
Coverage-based calculators assume the product is bought by a stated coverage rate or yield, then rounded to whole buying units after waste is added.
Common mistake
The usual mistakes are using the wrong coverage or yield rate, ignoring trimming losses, and comparing pack prices without checking what each unit really covers.
Next step links
Open the full Decorating Estimating tool set or go straight to the Primer Calculator.