Work out ceiling board quantity instantly with clear inputs, formula shown and shareable results.
Board count is ceiling area divided by the area of one board, uplifted ten percent because boards must be cut at walls and the offcuts are rarely reusable. Supporting framing at 400 mm centres runs one line per 400 mm of room width, each spanning the room length.
Board count
Boards = ceil(ceiling area / board area x 1.10)
Framing
Metres = (floor(width / 0.4) + 1) x room length
Boards = ceil(ceiling area / board area x 1.10). Board count is ceiling area divided by the area of one board, uplifted ten percent because boards must be cut at walls and the offcuts are rarely reusable.
Across, so the long edges are supported by several joists. Running them parallel puts every long edge on a single member and invites cracking at the joints.
This calculator takes 4 inputs: Room length, Room width, Board length, Board width. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.