Calculating Perimeter

Perimeter is the length, the linear measurement around a shape or structure – a room or an entire building. Perimeter can be used to estimate mouldings, edgings, or other basic building or finish materials.

Perimeter is equal to the sum of the sides. For a square this would be equal to four times one Side.


The perimeter for a rectangle can be calculated with the sum of the sides.

Another way to calculate the perimeter for a rectangle is to add twice the length plus twice the width.

(2 X L) + (2 X W) = PERIMETER
(2 X 20) + (2 X 12) = 64 FEET

Calculating perimeters in structures with offsets is no different. In the example below there is an offset in one corner. The perimeter can be calculated using the same formula, as the actual length of each side is the same as if there were no offsets.