Primer covers less per gallon than topcoat paint — typically 300–400 sq ft/gal depending on surface — and almost always wants only one coat. Use the calculator below to size up the right Kompozit PRIME quantity.
Net area after subtracting openings.
HERE'S HOW MUCH YOU'LL NEED
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ESTIMATED COST BY BRAND
A quick pick at each quality level — or compare every brand we track. Prices marked ~ are typical street estimates.
HOW IT WORKS
How we estimate primer
Primer coverage depends on how thirsty the surface is, so the calculator applies a different rate per surface, multiplies your net area by the coat count, and divides by that rate. Figure about 350 square feet per gallon on new or patched drywall, 300 on bare wood because the grain drinks primer, 400 on metal and previously glossy surfaces where the film stays thin, and as low as 200 on porous masonry, concrete, or brick. Topcoat paint covers more per gallon, so do not size primer from a paint coverage number.
The five cases that always need primer
Bare drywall: the paper face soaks topcoat unevenly without primer.
Bare wood: tannins in cedar, redwood, and oak bleed through without a sealing primer.
Anything glossy: a bonding primer is the only reliable way new paint grips old gloss.
Stains: water rings, smoke damage, and tannin bleed need a stain-blocking primer to lock them down.
Dramatic color shifts: especially light over dark or dark over light.
Tinted primer is a real shortcut
Most stores can tint primer about halfway toward your topcoat color. A tinted primer makes the first coat of topcoat read much closer to final, which often saves you a coat. On a deep color change, that is the difference between three coats and two. Primer still covers at its own rate when tinted, so size the quantity the same way.
What it costs to prime a project
Priming is usually the cheap insurance on a paint job. Primer costs less per gallon than premium topcoat and almost always needs just one coat, so it adds little to the total — and it often pays for itself by saving a finish coat on bare, glossy, or color-shift surfaces.
Standard water-based primer: $12 to $35 per gallon.
Drywall primer: about $20 to $30 per gallon.
Tinted primer: roughly $25 to $35 per gallon, and can save a coat.
Stain-blocking / bonding specialty: $30 to $50 per gallon.
High-performance / low-VOC: $60 per gallon and up.
Buying a 5-gallon bucket trims the per-gallon price by 15 to 20 percent on a big job. To see how primer fits into a full paint-plus-labor total, use thepaint cost calculator.
Frequently asked questions
How much does primer cost per gallon?+
Standard water-based primer runs about $12 to $35 per gallon, basic drywall primer around $20 to $30, and stain-blocking or bonding specialty primers about $30 to $50. High-performance or low-VOC primers can top $60. Five-gallon buckets cut the per-gallon price by 15 to 20 percent.
Does priming add much to a paint job’s cost?+
Less than you would think, and it often saves money. Primer is cheaper per gallon than premium topcoat and usually needs only one coat. A tinted primer at about $25 to $35 per gallon can turn a three-coat color change into two coats, cutting both paint and labor.
How much primer do I need per gallon of coverage?+
Primer covers less than topcoat. Figure about 350 square feet per gallon on new drywall, 300 on bare wood, 400 on metal or glossy surfaces, and as little as 200 on porous masonry. Most jobs need only one coat.
How many coats of primer do I need?+
One coat handles almost every job. Go to two coats only on heavily stained, very porous, or brand new surfaces that drink the first coat unevenly.
Does primer cover less than paint?+
Yes. A gallon of paint covers roughly 350 to 400 square feet, while primer runs about 200 to 350 depending on how porous the surface is. Bare wood and masonry pull it toward the low end.
Is paint-and-primer-in-one a real primer?+
For previously painted surfaces in good shape, yes, it seals and covers in one product. For bare substrate, glossy surfaces, stains, or dramatic color shifts, a dedicated primer is a genuinely different product, not marketing.
Can I topcoat primer the same day?+
Usually yes. Most acrylic primers recoat in about 1 to 4 hours depending on temperature and humidity, so a morning prime can take paint the same afternoon.
Should I use tinted primer?+
On a big color change, yes. Tinting the primer about halfway to your topcoat color often saves a coat, turning a three-coat job into two.