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Coffered ceiling layout calculator

Beam layout and on-center marks.

Open the Coffered Ceiling tool

Free. Runs in your browser, no account, and keeps working offline.

What it does

Enter the room's width and length, the width of the beams and how many coffers you want each way. The calculator sizes the coffers so they are all equal and gives the on-center spacing and a chalk-line mark for every beam centerline, measured from the wall.

Choose a border beam on every wall or interior beams only. A border beam frames the room and hides an out-of-square wall; interior-only leaves the coffers running to the walls.

The plan view shows the layout to scale, and the section lists give every beam and coffer in order, so the crew can snap lines and hang beam boxes without redoing the math on the ceiling.

Worked example

A 14′ × 18′ ceiling (168″ × 216″), 6″ wide beams with a border beam on every wall, 3 coffers across and 4 along.

Coffer, across the width
48″
Coffer, along the length
46 1/2″
Beam centerlines across, from the wall
3″, 57″, 111″, 165″
Beam centerlines along, from the wall
3″, 55 1/2″, 108″, 160 1/2″, 213″

Snap chalk lines on the centerlines, then hang the beam boxes on them.

Try it with your numbers

Questions

How do you lay out a coffered ceiling?

Subtract the total width of the beams from the room size, divide by the number of coffers to get the coffer size, then mark each beam centerline from the wall. Snap lines on the centerlines and build to them.

How wide should coffered ceiling beams be?

Common beam faces run from about 4″ to 8″, larger in bigger rooms. Enter yours and the coffers adjust.

What if the room isn't square?

Measure both walls. With a border beam on every wall, small differences disappear into the border.

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