Field guide / 04—08
Read paint coverage and coat count
Use the selected product's specifications, not one universal litres-per-wall figure.
Find coverage on the product label
Look for estimated square metres per litre for your product and surface. A published estimate can differ from actual use. Check whether it assumes one coat, a particular application method, or a prepared surface.
Calculate each coat
Estimated litres = net area × coat count ÷ coverage per litre per coat. If primer and finish paint are different products, estimate them separately. Round a purchase to the pack sizes actually offered by your supplier.
Check the surface and safety
Very porous or rough surfaces and a strongly contrasting old colour may need a different approach. Do not scrape or sand old coatings without checking material hazards; the EPA lead-paint guidance applies to a US context and does not replace local rules.