Ceiling Board Quantity Calculator

Work out ceiling board quantity instantly with clear inputs, formula shown and shareable results.

About Ceiling Board Quantity Calculator

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.

Formulas

Board count

Boards = ceil(ceiling area / board area x 1.10)

Framing

Metres = (floor(width / 0.4) + 1) x room length

Worked example

With the default values below, Ceiling Board Quantity Calculator returns Boards required of 8. Change any input above and every figure here is recalculated in your browser.

Inputs used

Room lengthminimum 0.1 m: 5 m
Room widthminimum 0.1 m: 4 m
Board lengthminimum 0.1 m: 2.4 m
Board widthminimum 0.1 m: 1.2 m

Results

Boards required: 8
Ceiling area: 20.00 m²
Area per board: 2.880 m²
Framing at 400 mm centres: 55.0 m

Step by step

1Values used
2Board count
3Framing
4Boards required= 8
5Ceiling area= 20.00 m²
6Area per board= 2.880 m²
7Framing at 400 mm centres= 55.0 m

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is the Ceiling Board Quantity figure worked out?

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.

Should boards run along or across the joists?

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.

What values do I need to enter?

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.