Paint quantity and cost calculator

How many gallons of paint a room's walls need, how many to buy, and what they cost, from the room size, doors, windows and coats.

Room length (ft)

Room width (ft)

Wall height (ft)

Number of doors

Number of windows

Coats

Coverage (sq ft per gallon)

Price per gallon ($)

How it works

Wall area is 2 times the length plus the width, times the wall height. It takes off 21 square feet for each door and 15 for each window, a common allowance for standard sizes.

Gallons needed are the wall area times the coats, divided by the coverage.

Paint comes in whole gallons, so gallons to buy are rounded up from the unrounded gallons needed. Paint cost is gallons to buy times the price per gallon.

Coverage varies by paint and surface. 350 square feet per gallon is a common figure on the can; use the one on yours.

Want to quote whole painting jobs, in a spreadsheet? Painting Estimate and Quote Calculator, Excel and Google Sheets, $24.

This is arithmetic on the numbers you enter. It is not tax, legal or financial advice.