**How To Calculate Floor Plan**. Look around at all the floor that will need to be covered. Measure the width of your room in metres.

The result is the Floor Area Ratio FAR. The number of possible story propers is calculated based on the gross floor area and the value for the constructible land area. Gross Floor Area G Floor Area of 1st Story Floor Area of 2nd Story for all floors above the ground STEP 4.

### Multiply the two figures together 1458 x 125.

In this example the square footage of the room would be 18225 square feet. To calculate the floor plans square footage you will need to obtain a current copy of the floor plan. Obtain Square Foot Calculation Standard. FAR Gross Floor Area Area of the plot FAR is used for developing the zoning codes by the governments planning department.