FSI / FAR Calculator

Enter your plot area and the applicable FSI or FAR value to calculate the total permissible built-up floor area. Optionally add a floor count for an indicative per-floor breakdown.

Plot area × FSI = what you can build.

Plot area unitPlot area (sq ft)

sq ft

FSI / FAR valueNumber of floors (optional)Used for indicative floor-area breakdown only

Total permissible floor area

Total Floor Area = Plot Area × FSI/FAR. FSI (Floor Space Index) and FAR (Floor Area Ratio) are equivalent terms. The floor-count breakdown is indicative — actual usable area per floor depends on local building regulations, setbacks, and ground coverage limits.

Why Use FSI / FAR Calculator?

Total Floor Area = Plot Area × FSI — pure math, no assumptions
FSI and FAR are equivalent — enter either
Supports sq ft, sq m, acre, hectare, and Indian regional units
Indicative floor breakdown when you enter a floor count
Results in input unit + sq ft + sq m reference
No city or state FSI database — you enter the applicable value
100% private — all calculations run in your browser

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Frequently Asked Questions

FSI stands for Floor Space Index (also called FAR — Floor Area Ratio). It is the ratio of total permissible built-up floor area to the plot area. Formula: Total Floor Area = Plot Area × FSI. For example, a 2,400 sq ft plot with FSI 2.0 allows a maximum total floor area of 4,800 sq ft across all floors.