Construction
Ceiling Area Calculator
Calculate ceiling area from room length and width for boards, paint or panels.
Formula
Ceiling area = room length multiplied by room width, for a rectangular ceiling.
How it works
Measure the room at floor level, since ceilings usually match the floor footprint. The area gives a base figure for plasterboard, paint or ceiling panels. Add a waste allowance for cutting when ordering materials.
FAQs
What if the ceiling is sloped?
Measure each sloped plane separately using its true length and width, then add the planes together.
Do I subtract light fittings?
For material ordering, usually not: the small saving is absorbed by cutting waste.
How much waste for boards?
Around ten percent is a common allowance, more for rooms with many corners.
Rough estimate only — consult a licensed professional for structural work before building.