Calculate floor area ratio from gross floor area and lot size, or solve for max buildable floor area, required lot size, lot coverage, and unused FAR.

Required: gross floor area (or floor plate and stories) plus lot area.

Sum of the floor area of every story. This unit also applies to the advanced floor-area fields.

Add your zoning FAR cap to check compliance and see unused development rights.

Advanced options: exclusions, footprint, coverage, land value +
Calculator Operations Required Inputs
Convert Floor to Area Ratio Gross Floor Area, Buildable Land Area
Convert Gross Floor Area Floor to Area Ratio, Buildable Land Area
Convert Buildable Land Area Gross Floor Area, Floor to Area Ratio

Floor to Area Ratio Formula

The following formula is used to calculate the floor-to-area ratio.

FAR = G / B
  • Where FAR is the floor to area ratio
  • G is the gross floor area (sum of the area of all floors)
  • B is the buildable land area (parcel width X parcel depth)

To calculate the floor to area ratio, divide the gross floor area by the buildable land area.

Floor to Area Ratio Definition

A floor to area ratio is defined as the ratio of the gross floor area to buildable land area and is a measure of how many floors can be built in a given parcel or lot of land.

Floor to Area Ratio Example

How to calculate a floor to area ratio?

  1. First, determine the gross floor area.

    Sum all of the areas of each story in the potential building to determine the gross floor area.

  2. Next, determine the buildable land area.

    Calculate the total possible land area that can be built on by multiplying the parcel width by the parcel depth.

  3. Finally, calculate the floor to area ratio.

    Calculate the floor to area ratio using the equation above.

FAQ

What is a floor to area ratio?

A floor to area ratio is a measure of the ratio of a building floor area to the size of the lot of the property.

floor to area ratio
floor to area ratio calculator