FAR / FSI calculator

Maximum built-up area from plot area and FAR, or the FAR of a design.

  • Free, no sign-up
  • Runs in your browser
How it is calculated

FAR (FSI) = total built-up floor area ÷ plot area. Maximum built-up area = plot area × permitted FAR. Floors needed ≈ built-up area ÷ floor plate.

Check locally: This is a generic calculation. What counts towards FAR (balconies, stairs, parking, basements), premium FSI and the permitted value are set by your local development rules.

How to use the FAR / FSI Calculator

Find the maximum built-up area allowed on a plot from its floor area ratio (FAR), also called floor space index (FSI), and check a proposed design against it.

  1. Enter the plot area.
  2. Enter the permitted FAR or FSI from the development control regulations.
  3. Optionally enter a typical floor plate to see how many floors that allows.
  4. Optionally enter your proposed built-up area to check it against the limit.

Worked example

A 500 m² plot with a permitted FAR of 1.5 allows 750 m² of built-up area (about 8,073 ft²). With a 200 m² floor plate that is 3.75 floors, so three full floors and part of a fourth.

Good to know

  • What counts towards FAR (balconies, stairs, lift cores, parking, basements) differs between cities, so check the local rules.
  • Premium FSI, TDR and road-widening benefits can raise the base FAR in many Indian cities.
  • FAR limits floor area, while setbacks, height limits and ground coverage limit the footprint and form.

Questions

Is FAR the same as FSI?

Yes. Floor Area Ratio and Floor Space Index are two names for built-up floor area divided by plot area.

Does it apply my city's rules?

No. It is a generic calculation; your local rules decide what is counted and the permitted value.

Is anything I enter saved or sent?

No. The calculation runs in your browser. Nothing you type is sent anywhere. You can copy the result, print it or download it as a CSV.