A drop ceiling hangs a metal grid on wires below the old ceiling or the joists. Main tees run the length of the room, cross tees clip between them, and the panels drop into the openings.
How to use this calculator
- Measure the room wall to wall, length and width.
- Pick the panel size.
- Under More options, enter the number of panels in a carton of the panel you like.
- Check the borders: the layout keeps them equal on opposite walls and at least half a panel wide.
Worked examples
A basement room
Room: 20 × 14 ft · Ceiling panels: 2 x 4 ft
- Ceiling panels
- 40 panels
- Main tees, 12 ft
- 7
- Cross tees, 4 ft
- 38
- Wall molding, 12 ft pieces
- 7
- Hanger wires
- 18
- Cartons of 8 panels
- 5
- Ceiling area
- 280 sq ft
- Border along the long walls
- 3.00 ft
- Border along the short walls
- full panels
A small office in 2x2 panels
Room: 12 × 11 ft · Ceiling panels: 2 x 2 ft
- Ceiling panels
- 36 panels
- Main tees, 12 ft
- 3
- Cross tees, 4 ft
- 16
- Cross tees, 2 ft
- 19
- Wall molding, 12 ft pieces
- 5
- Hanger wires
- 8
- Cartons of 16 panels
- 3
- Ceiling area
- 132 sq ft
- Border along the long walls
- 3.50 ft
- Border along the short walls
- full panels
A large rec room
Room: 30 × 22 ft · Ceiling panels: 2 x 4 ft
- Ceiling panels
- 90 panels
- Main tees, 12 ft
- 16
- Cross tees, 4 ft
- 89
- Wall molding, 12 ft pieces
- 10
- Hanger wires
- 40
- Cartons of 8 panels
- 12
- Ceiling area
- 660 sq ft
- Border along the long walls
- 3.00 ft
- Border along the short walls
- full panels
A laundry room
Room: 9 × 7 ft · Ceiling panels: 2 x 2 ft
- Ceiling panels
- 20 panels
- Main tees, 12 ft
- 2
- Cross tees, 4 ft
- 9
- Cross tees, 2 ft
- 11
- Wall molding, 12 ft pieces
- 4
- Hanger wires
- 3
- Cartons of 16 panels
- 2
- Ceiling area
- 63 sq ft
- Border along the long walls
- 3.50 ft
- Border along the short walls
- 1.50 ft
How the grid is laid out
Main tees run the long way, 4 ft apart, and the long cross tees clip into them every 24 inches. For 2x2 panels, short cross tees split each opening in half. Main tees come in 12 ft lengths and are joined end to end; wall molding in 12 ft pieces runs around the room.
Armstrong's layout centers the grid so the border panels on opposite walls are the same size, and looks best when no border is narrower than 10 inches. USG suggests adding 5 percent to each grid count for mistakes, which the calculator does.
Hanging it
- Hanger wires go along the main tees no more than 4 ft apart. Armstrong allows wire of 12 to 16 gauge in homes.
- Leave about 6 inches of wire below the main-tee line to bend and twist around the tee.
- Allow at least 3 inches between the grid and the ceiling above to tilt panels in, at least 4 inches below an existing drywall ceiling, and USG suggests 4 inches below the lowest duct or pipe. Recessed lights need more.
Panels per carton
Carton counts vary by product. One common panel comes 8 panels to a carton in 2x4 and 16 panels in 2x2; check the label of the panel you choose and enter it under More options.
Common questions
How do I calculate how many ceiling tiles I need?
Lay out the grid with equal borders, then count the openings, cut borders included, since each cut border panel uses up a whole panel. The calculator does the layout and counts the cartons.
How far apart are main tees in a drop ceiling?
4 ft apart, center to center, with long cross tees every 24 inches between them.
How much clearance do I need for a drop ceiling?
At least 3 inches above the grid to tilt panels in, more under drywall or ducts, and more again for recessed lights.
How far apart should hanger wires be?
No more than 4 ft apart along each main tee.
Should I use 2x2 or 2x4 ceiling panels?
2x4 panels need fewer tees and go up faster; 2x2 panels look more like a finished ceiling and are easier to handle and cut. The calculator counts the grid for either.