Measure the length and width of the room and jot down the measurements on a piece of paper.
Divide the panel length into the room's width. Add the panel's length to the equation's remainder. For example, if the panel's length is 4 feet and the remainder is 1 foot, the result is 5 feet. Divide this number in half for length of the border panel. For a 4 foot panel in a 9-foot wide room, the result is 2 feet 6 inches.
Calculate the panel widths by dividing the room's length by the panel's width. Add the panel's width to the equation's remainder. For example, if the panel's width is 2 feet and the remainder is 6 inches, the result is 2 feet 6 inches. Divide this number in half for width of the border panel. In this example, the result is 1 foot 6 inches.
Cut the panels using a utility knife. First measure the panels to fit the previous height and width measurements. Use a straightedge and cut halfway through the ceiling tile. Bend the tile at the cut and cut the rest of the way through.