Painting contractors need fast, accurate material estimates to prevent mid-job runouts or excess waste when pricing interior latex projects on standard drywall.
Enter wall area
Applies the standard 350 square feet per gallon coverage rate for single-coat interior latex paint on smooth drywall.
How to Use This Paint Gallon Calculator
Enter the total square footage of all walls to be painted.
Type the exact number of finish coats you will apply.
Pick your wall texture or color-difference scenario.
Read the live gallon total; purchase the whole-gallon amount shown.
FAQ
Q: How much area does one gallon of interior paint actually cover?
A: Standard interior latex covers 350 square feet per gallon on smooth drywall for a single coat; textured walls or major color shifts reduce this to roughly 250 square feet per gallon.
Q: Should I always round paint gallons up even if the calculator shows decimals?
A: Yes, buy whole gallons because manufacturers do not sell partial containers and mixing different production batches causes visible sheen and shade mismatches.
Q: Does primer volume count toward the gallon requirement in this tool?
A: No, this generator estimates topcoat volume only; evaluate primer needs separately based on substrate porosity.
Q: Why does my output sometimes exceed simple area-divided-by-350 math?
A: The calculator forces ceiling rounding to the nearest whole gallon and applies reduced coverage multipliers for textured or high-contrast surfaces to account for real-world absorption and cut-in waste.