Basement paint calculator

A typical basement needs about 3 gallons + 1 quart

Based on a standard 24 × 20 ft basement with 7.5-ft ceilings, the walls work out to about 609 sq ft after subtracting 1 door and 2 windows. A standard two-coat repaint needs roughly 3 gallons + 1 quart of quality interior paint. The recommended finish for a basement is eggshell — more on why below.

Test For Moisture Before You Paint

Paint cannot stop water; it only hides a problem until it peels. Tape a two-foot square of plastic sheet tightly to a foundation wall and leave it 24 to 48 hours. Condensation under the plastic means vapor is pushing through the wall, and any topcoat will bubble within a year. Fix the source first — grading, gutters, interior drainage, or a masonry waterproofer rated to hold back vapor — then paint. On a dry wall, a standard interior coat is fine.

Block Walls Drink More Paint

Bare concrete block soaks paint into its open pores and mortar joints, so a CMU basement burns roughly 25 to 30 percent more than the calculator's drywall estimate, and the first coat may look blotchy. A masonry block filler or primer levels that porosity and saves you a topcoat of expensive finish paint. Painted-drywall basements behave like any normal room and match the estimate closely; it is the unfinished block and parging that throw the math off.

Use A Mildew-Resistant Finish

Basements stay cooler and damper than the rest of the house, which is exactly what mildew likes. Choose an eggshell or satin with a mildew-resistant additive, or a product formulated for below-grade and high-humidity spaces. Eggshell hides the lumps and trowel marks of block and old foundation walls better than a shinier sheen. Run a dehumidifier during and after painting; a film that cures in damp air is slower to harden and quicker to grow spots.

Paint The Low Ceiling Light, Too

At 7.5 ft, the ceiling is the basement's real constraint, not the floor plan. A stark white ceiling over colored walls draws a hard line that announces how low the room is. Painting the walls and ceiling the same light, soft color blurs that edge and lets the eye read the space as taller. Light walls also bounce what little daylight the small windows let in, so the whole room feels less like a basement.

How the basement paint math works

Wall area is perimeter × ceiling height: (2 × 24 + 2 × 20) = 88 ft of perimeter, times a 7.5-ft ceiling, equals 660 sq ft of gross wall. We subtract 21 sq ft per door and 15 sq ft per window, leaving about 609 sq ft of paintable wall. Multiply by the number of coats, divide by a coverage rate of about 388 sq ft per gallon, and round up to the nearest quart — that is the number you take to the store. Change any input in the calculator above and it recalculates instantly.

Paint needed by coats

Two coats is the right default for almost every repaint. Use one coat only for a same-color refresh, and three for dark-over-light changes or vivid colors that cannot hide in two. The ceiling adds 480 sq ft (length × width) when you choose to paint it — usually a separate flat-white product, so most people buy a dedicated gallon for it.

What it costs to paint a basement

Doing it yourself, the paint for two coats runs about $130–$228 (roughly 3.25 gal at $40–$70 a gallon), plus $50–$100 in supplies — rollers, brushes, tape, trays, and a drop cloth. That is your whole cost if you bring the labor.

Hiring a painter changes the math: most pros charge $2–$5 per square foot of floor area, so a 480 sq ft basement lands around $960–$2,400. Labor is 75–95% of an interior bill because prep, cutting in, and cleanup eat the hours. For a full paint-plus-labor breakdown, use the paint cost calculator.

Paint cost by brand

Coverage is similar (about 350–400 sq ft per gallon) across the major interior lines, so the price tier is what moves your bill. These are current per-gallon prices for the brands the calculator can price for you — pick one in the result panel above and it multiplies your gallons for this basement into an exact paint cost:

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