# Floor Space Index (FSI) Explained

> Floor space index (FSI), or floor area ratio (FAR), caps the built-up area on a plot. See the meaning, a 5,000 sq.ft example and where approvals are kept.

Canonical: https://superwise.site/glossary/floor-space-index/
Last updated: 2026-11-01

The ratio of a building's total floor area to its plot area, which caps how much a developer may build on the plot.

## What is Floor Space Index (FSI) / FAR?

Floor Space Index (FSI), also called Floor Area Ratio (FAR), is the ratio of a building's total floor area to its plot area. The local municipal authority, such as the BMC in Mumbai, sets the maximum permitted FSI, which caps the [built-up area](https://superwise.site/glossary/built-up-area/) on the plot. An FSI of 2.0 on a 10,000 sq.ft plot allows 20,000 sq.ft of floor space at most.

## Practical example

A developer buys a 5,000 sq.ft plot in a zone with an FSI of 3, so the developer is legally allowed to build 15,000 sq.ft of floor area in total. The developer can choose a taller, narrower tower (for example, 10 floors of 1,500 sq.ft each) or a shorter, wider building, as long as it meets the setback and height restrictions.

## In SuperWise

In SuperWise, the sanctioned plan and the municipal approval that fix the permitted FSI are kept as project documents. Each document has a folder, a purpose, a stage and a revision history, and it can be linked to a schedule node. Folder access is set per role.

[Document management system](https://superwise.site/features/document-management-system/)

## Related terms

- [Built-up Area](https://superwise.site/glossary/built-up-area/)
- [Zoning Laws (Development Control Rules)](https://superwise.site/glossary/zoning-laws/)

## Related
- [Built-up Area](https://superwise.site/glossary/built-up-area/)
- [Zoning Laws (Development Control Rules)](https://superwise.site/glossary/zoning-laws/)
- [Document management system](https://superwise.site/features/document-management-system/)