Primer Calculator | Free Construction Calculators

Calculate how much primer you need for your painting project.

sq ft
sq ft
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When to Use Primer

  • New Drywall: Always prime unpainted drywall
  • Bare Wood: Seals wood and prevents tannin bleed
  • Color Changes: Dark to light or dramatic color shifts
  • Stained Surfaces: Water damage, smoke, or other stains
  • Glossy Surfaces: Helps paint adhere to slick surfaces
  • Porous Surfaces: Seals surfaces like concrete or brick

Primer Types

Standard/Multi-Purpose Primer

General use, new drywall, minor repairs. Most economical option.

Stain-Blocking Primer

Covers stains, water damage, smoke damage, prevents bleed-through.

High-Hide Primer

Excellent for covering dark colors, dramatic color changes.

Bonding Primer

For glossy, slick, or hard-to-paint surfaces like tile or laminate.

Tinted Primer

Can be tinted close to final color for better coverage.

Primer Coverage

  • Standard Rate: 300-400 sq ft per gallon
  • Smooth Surfaces: Up to 400 sq ft per gallon
  • Porous Surfaces: 200-300 sq ft per gallon
  • Textured Surfaces: 250-350 sq ft per gallon

Number of Coats

  • 1 Coat: Most situations, new drywall, minor repairs
  • 2 Coats: Heavy stains, severe color changes, very porous surfaces

Primer Application Tips

  • Apply primer in thin, even coats
  • Allow primer to dry completely (usually 1-4 hours)
  • Light sanding after primer creates smooth finish
  • Tint primer toward final paint color for better coverage
  • Use appropriate primer for surface type

When You Can Skip Primer

  • Previously painted walls in good condition
  • Repainting same or similar color
  • Using paint with built-in primer
  • Minor touch-ups on existing paint

Surface-Specific Guidance

  • New Drywall: Use PVA or drywall primer
  • Wood: Oil-based or shellac primer for knots
  • Metal: Rust-inhibiting metal primer
  • Masonry: Concrete/masonry-specific primer
  • Previously Painted: Bonding primer if switching paint types

Benefits of Using Primer

  • Better paint adhesion and durability
  • Improved paint coverage (may need fewer coats)
  • More uniform color appearance
  • Seals porous surfaces, saves paint
  • Prevents stains from bleeding through
  • Professional-looking finish