# Open Space Ratio (OSR) Meaning

> The open space ratio (OSR) is the share of a plot kept unbuilt under planning rules, often 10% to 15%. See a township example and how SuperWise files layouts.

Canonical: https://superwise.site/glossary/open-space-ratio/
Last updated: 2026-11-01

A town planning rule that keeps a set percentage of a plot unbuilt and open to the sky as parks, playgrounds or greenery.

## What is Open Space Ratio (OSR)?

The Open Space Ratio (OSR) is the share of a plot that planning rules require to stay free of built structures and open to the sky, as gardens, playgrounds or greenery. City authorities enforce it to limit overbuilding, and the required share is frequently 10% to 15% of the total plot area.

## Practical example

A builder buys a 10-acre plot for a township, but local OSR rules require 10% open space. The builder cannot put buildings or paved roads on 1 acre of the plot and must design that acre as a central park to get the [layout plan](https://superwise.site/glossary/layout-plan/) approved.

## In SuperWise

SuperWise keeps the approved layout plan that shows the open space as a project document, with a stage such as Approved or Superseded and a revision history. A document can also be linked to the schedule nodes it governs.

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

## Related terms

- [Layout Plan](https://superwise.site/glossary/layout-plan/)
- [Floor Space Index (FSI) / FAR](https://superwise.site/glossary/floor-space-index/)

## Related
- [Layout Plan](https://superwise.site/glossary/layout-plan/)
- [Floor Space Index (FSI) / FAR](https://superwise.site/glossary/floor-space-index/)
- [Document management system](https://superwise.site/features/document-management-system/)