How the calculator works
It adds the area of every door, both sides if you choose, the drawer fronts, and the face frames and end panels, counted as about 1.5 sq ft per foot of cabinet run. It multiplies by the number of coats and divides by 400 sq ft per gallon, the usual coverage for cabinet enamel on a sanded surface, plus 10% for waste.
Why the paint amount is small
A typical kitchen needs only one to two gallons of finish paint. The work is in the preparation: removing doors and hardware, degreasing, sanding, priming and letting each coat dry fully. Plan several days, not a weekend.
Choosing paint for cabinets
Use a paint made for cabinets and trim, such as a water-based enamel or urethane-modified alkyd. These level out to a smooth finish and harden into a surface that resists knocks and cleaning. Satin and semi-gloss are the usual sheens.
Primer on cabinets
Prime glossy, bare or stained wood, and use a bonding primer on laminate or thermofoil. Skipping primer is the most common reason cabinet paint peels or chips.
Results are estimates. Coverage depends on the product, the tools and the wall; the rate printed on your can wins.