中文：

套户比是指每套房屋的建筑面积与每户平均建筑面积的比值，通常用来衡量一个住宅小区的平均户型大小。

套户比的计算公式为：套户比 = 每套房屋的建筑面积 / 每户平均建筑面积。这个比值越小，说明小区的户型越小，适合的居住人口也就越少；反之，比值越大，说明小区的户型越大，适合的居住人口也就越多。

套户比对于购房者来说具有重要的意义。了解一个住宅小区的套户比可以帮助购房者更好地了解该小区的户型分布和平均户型大小，从而更好地选择适合自己的房源。同时，套户比也是衡量一个住宅小区规划设计是否合理的重要指标之一。

英文：

The ratio of housing units refers to the ratio of the building area of each housing unit to the average building area per household, which is usually used to measure the average size of the average household in a residential community.

The calculation formula of the ratio of housing units is: the ratio of housing units = the building area of each housing unit / the average building area per household. The smaller this ratio is, the smaller the household size of the community is, and the fewer people suitable for living; conversely, the larger the ratio is, the larger the household size of the community is, and the more people suitable for living.

The ratio of housing units is of great significance to home buyers. Understanding the ratio of housing units in a residential community can help home buyers better understand the distribution of household types and the average household size in the community, so as to better choose a suitable property. At the same time, it is also one of the important indicators to measure whether the planning and design of a residential community is reasonable.