Room Area Calculator
The simplest calculator on the site: length × width in square metres. It is the starting point for nearly every other calculation — flooring, painting, heating, cooling and furniture planning all begin here.
Enter your measurements
Your m² of floor area result will appear here instantly.
How to use this calculator
- 1
Measure the length of the room at its widest point, wall to wall.
- 2
Measure the width the same way, at right angles to the length.
- 3
Enter both measurements in the same unit — metres or centimetres.
- 4
For L-shaped or odd-shaped rooms, split them into rectangles, calculate each, and add the areas yourself.
How the calculation works
Area
Area = length × width. A 5 m × 4 m room is 20 m². If you measured in centimetres, we convert to metres first — 500 cm × 400 cm = 20 m².
Worked example
A bedroom measures 4.2 m long and 3.1 m wide.
Area = 4.2 × 3.1 = 13.02 m².
The room is approximately 13 m² — the figure you'd feed into a flooring or heating calculation.
Frequently asked questions
How do I measure an L-shaped room?
Divide it into two rectangles that share an edge, measure each separately, and add the two areas. A 5 × 4 m room with a 2 × 1.5 m alcove is 20 + 3 = 23 m².
What is a typical Australian bedroom size?
It varies widely by home and era. Rather than quoting averages, measure your own room — it takes a tape measure thirty seconds and beats any estimate for planning materials.
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Results are estimates only. Always confirm material requirements with your supplier or a qualified professional before purchasing.