How Many Gallons of Paint?
Calculate paint gallons for any room by dimensions. Doors, windows, and coats included.
Paint Coverage Math
One gallon covers 350-400 square feet per coat on smooth surfaces. Textured walls absorb more — drop coverage to 250-300 sq ft/gallon. Dark-to-light color changes need a coat of primer plus two coats of paint (essentially 3 coats). Same-color touch-ups need only one coat. Calculate wall area: room perimeter x wall height, subtract 21 sq ft per door and 15 sq ft per average window. A 14x12 room with 8-foot ceilings, 2 doors, and 3 windows: 416 - 42 - 45 = 329 sq ft of paintable surface.
Why You Should Always Buy Extra
Buy 10-15% more paint than calculated. Three reasons: first, textured surfaces and porous patches absorb more than expected. Second, roller and brush waste accounts for 5-8% loss. Third — and most importantly — you need leftover paint for future touch-ups. Matching paint later is surprisingly difficult even with the same color code, because different production batches have subtle variations visible on the wall. Keep your leftover paint sealed with the color code written on the lid.
Buy all paint from the same batch — different batches can have subtle color variations visible on the wall.
