# Building coverage ratio (建筑密度)

> Building coverage ratio is the percentage of a plot covered by the building's footprint. A 100 m² plot with an 80 m² footprint has 80% coverage; the maximum is set by building codes and the local zoning plan.

- Vietnamese: Mật độ xây dựng
- English: Building coverage ratio
- Chinese: 建筑密度
- Chinese characters: 建筑密度
- Also called: Mật độ xây dựng · Site coverage

## Explanation

The maximum usually falls as plots get larger: small urban plots may be built almost fully, while large plots must keep more open ground. Detailed zoning for an area may be stricter than the general code.

Coverage is not the same as floor area ratio, which divides the total floor area of all storeys by the plot area.

## How Home Check uses it

When designing, Home Check advises a sensible coverage and number of storeys under Vietnamese building codes, and the assistant can explain the regulations and name the document. — [House design](https://myhomecheck.ai/design)

## Related terms

- [Setback](https://myhomecheck.ai/learn/glossary/setback): The setback is the distance from the street boundary line (between road land and the plot) to the building line (which the house may not cross).
- [Light well](https://myhomecheck.ai/learn/glossary/light-well): A light well is a vertical void open to the sky that brings light and air into the middle of a house.

## Questions

### Does a light well count toward coverage?

An open light well is often excluded from the footprint, but the exact method follows local rules — check before applying for a permit.

### What is the maximum coverage?

It depends on plot size, building type and the zoning plan. Check the detailed plan and the current code where you build.

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Original page: https://myhomecheck.ai/learn/glossary/building-coverage-ratio  
Other languages: [Tiếng Việt](https://myhomecheck.ai/vi/tri-thuc/thuat-ngu/mat-do-xay-dung/index.md) · [中文](https://myhomecheck.ai/zh/learn/glossary/building-coverage-ratio/index.md)  
Updated: 2026-10-21