Primer Calculator
Use this primer calculator to answer how much primer do I need for a project. Enter square footage, coats, and waste to get gallons and quarts for ordering.
Inputs
Tip: Primer coverage is often lower than paint. Start around 250 sq ft per gallon and adjust to your product label.
Results
Gallons required
5.28
Adjusted area: 1,320 sq ft
Quarts equivalent
21.12
Based on 250 sq ft per gallon.
Assumptions
- Square footage includes all surfaces you plan to prime.
- Coverage per gallon depends on surface porosity and product spec.
- Waste accounts for roller loss, cut-in work, and touch-ups.
Example
A 1,200 sq ft job with 1 coat(s) and 10% waste needs about 5.28 gallons of primer.
FAQ
How much primer do I need per square foot?
Most primers cover around 200–300 sq ft per gallon, so divide adjusted square footage by your product's coverage rate.
Should I prime before every paint job?
Primer is recommended on new drywall, stains, raw wood, or major color changes to improve adhesion and coverage.
Do I need more primer for porous surfaces?
Yes. Rough or porous surfaces soak up more primer, so increase waste or lower coverage per gallon.