How to use this calculator
Measure two adjacent sides. For a square, enter the same measurement for length and width.
Formula
A = l × w; P = 2(l + w)
Worked example
A rectangle 8 m long and 5 m wide has area 8 × 5 = 40 m² and perimeter 2 × (8 + 5) = 26 m.
Assumptions and limits
Opposite sides are assumed parallel and corners are right angles. For an L-shaped room, split it into non-overlapping rectangles.
Frequently asked questions
How do I calculate a square?
Enter equal length and width. A square with side 4 m has area 16 m².
What units should I use?
Choose your input unit, then enter every dimension in that unit. The result unit can be changed independently.
Does this include waste or material costs?
No. This is geometric area only. Add openings, overlap, cutting waste, prices and installation requirements separately.
Calculated locally; rounded only for display.