Do It Yourself: How Much Paint Do You Need? (The Paint Quality Institute)

Start by measuring the interior room or exterior area
you want to paint.

Enter the correct number in feet (round up to the nearest foot)
in each of the boxes to the right.

interior/exterior wall width 1			* interior ceiling length
interior/exterior wall width 2			* interior ceiling width
interior/exterior wall width 3			* Enter 0 if you are not painting the ceiling.
interior/exterior wall width 4			* Enter 0 if you are not painting the ceiling.

Enter your ceiling height or exterior wall height here.

Then click the calculate button.