Bathroom Paint Calculator — Paint Needed & Painting Cost

The math behind how much paint a bathroom needs is four steps, and the calculator above runs all of them on every input change. First, gross wall area: two wall pairs times ceiling height, or 2 × (length + width) × height. The default 6×10 bathroom with 8-foot ceilings carries 2 × (6 + 10) × 8 = 256 sq ft of gross wall.

Second, subtract everything that never gets painted. A standard 3×7 door removes 21 sq ft, a typical 3×5 window 15 sq ft, and — the deduction unique to bathrooms — the tiled wet area. A standard 60×30 alcove tub with a surround tiled to 72 inches removes about 66 sq ft across three walls, more than a quarter of this bathroom's walls. That leaves 256 − 21 − 15 − 66 = 154 paintable square feet, plus the 60 sq ft ceiling.

Third, multiply by coats and divide by coverage: (154 + 60) × 2 coats ÷ 350 sq ft/gal = 1.22 gallons theoretical. Fourth, add the planning buffer and separate it from the purchase decision: 1.22 × 1.10 = 1.35 gallons including waste, which rounds to 2 purchased gallons. The theoretical figure (1.22) and the purchase figure (2) are deliberately displayed apart in the output because they answer different questions — how much film the walls need versus what goes in the shopping cart.

Primer is mandatory — not optional — in four bathroom scenarios: bare drywall or fresh joint compound, a dramatic color change, water or smoke stains, and any glossy or oil-based previous finish being painted without full sanding. One coat at 300 sq ft per gallon covers a typical bathroom's paintable walls and ceiling with room to spare; the calculator sizes it from the same area as the finish paint, times the primer coat count you set.

Two primer coats is the exception for heavy stains and dark-to-light changes, and the calculator carries that as a separate input because it doubles the primer line independently of the finish line. Stain-blocking products (shellac- or oil-based) sit at the low end of the coverage range — plan closer to 250 sq ft/gal when the deduction list includes old leak stains around a tub flange.

Tinting the primer toward the final color is the cheapest hiding upgrade available: a gray-tinted primer under a deep navy costs the same as white primer and routinely saves a third finish coat. In quantity terms it changes nothing — primer gallons are primer gallons — which is why the cost output keeps finish and primer lines separate instead of blending them.

The optional labor estimate in the calculator (painted area × your local rate, ±20%) exists so a DIY decision has a number attached — at $1.20–$1.80 per painted square foot, a typical 6×10 bathroom's painter labor runs roughly $260–$390, against about $114 of materials. DIY is the overwhelming default for bathrooms: painting is the most DIY-eligible trade in the remodel — unpermitted, unfined, reversible — and the site's main estimator pre-checks it in Partial DIY mode.

Hire a professional when the schedule is tight, the walls carry damage history (smoke, repeated moisture failures, glossy oil paint) that needs real prep, or the bathroom is part of a contractor-run remodel where the painter is already in the crew. Otherwise a careful homeowner with good rollers, real cut-in patience and a weekend matches a rushed crew — the arithmetic gap ($260–$390) is the labor share you keep.

For the rest of the room's budget, use the main bathroom calculator — painting is one line among eight trades there, and whole-room scope (tile, vanity, flooring) is its job, not this page's.