Primer picker — match the problem, not the brand
Primer is a tool with a job: seal porous drywall, block stains, stick to slick oil, or hide a dark color. Buying any white primer wastes money when you need stain-block or bonding chemistry.
First identify what is on the wall with the oil vs latex test. Then use the table below.
Which primer for which wall
More context on when to skip primer lives in Should I use primer before painting?.
- New drywall / large mud patches → PVA or drywall primer (cheap, high coverage)
- Water stains, smoke, nicotine, crayon → stain-blocking primer (shellac or labeled water-based stain blocker)
- Glossy oil enamel or hard slick surfaces → bonding / adhesion primer after light sanding
- Dark red, navy, black → light → tinted primer (gray or toward finish color)
- Clean latex, similar color refresh → often skip primer; spot-prime patches only
- Bare wood trim before wall paint → wood primer on trim; walls still get their own product
How much primer to buy
Interior primers often cover 200–300 sq ft per gallon — less than finish paint. Count one full coat over every wall you will prime. Large color changes or porous new drywall may need a second primer coat.
Estimate finish paint separately in the how much paint calculator. Add primer gallons as a second pass of the same wall area at ~250 sq ft/gallon if your can does not list coverage.
Apply primer like finish paint
Next: gather tools and supplies, then follow how to paint a room step by step.
- Stir thoroughly; do not thin unless the label allows
- Cut in edges, then roll; keep a wet edge
- Sand lightly with 220 grit if grain raises on drywall primer
- Recheck stain bleed — second coat of stain-blocker if marks show through
- Topcoat within the recoat window on the can (often same day for latex primers)