Square Footage Calculator

Calculate rectangular floor area after a cut-out, then add a waste allowance for material planning.

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One rectangular room minus one rectangular cut-out. Set cut-out dimensions to zero if none. Switching units reinterprets these measurements.

Net floor area

114 ft²

  • Net area in m²10.59094656
  • Material including waste (ft²)125.4
  • Cut-out (ft²)6

How this was calculated

Net area = room length × width − cut-out length × width.

Order area = net area × (1 + waste/100). Round up to the supplier’s pack size separately.

Method

Gross area = length × width. Net area subtracts the rectangular cut-out. Order area = net area × (1 + waste percentage/100).

Worked example

A 12 ft by 10 ft room is 120 ft². Subtract a 2 ft by 3 ft cut-out to get 114 ft². Adding 10% waste gives 125.4 ft² of material before rounding to whole packs.

Assumptions and limits

This is a one-room rectangular model. For irregular rooms, split the plan into nonoverlapping rectangles and sum their areas. Cut-outs must fit within the room. Waste varies by material, pattern and installation method.

Last updated . Results are estimates for informational purposes only.