Calculate residential density in dwellings per hectare using site area and proposed homes. Compare gross and net density, understand the likely density band and sense-check whether a scheme feels low, typical or high density.
Gross density normally uses the whole site area. Net density normally focuses on the developable residential area, excluding major open space, main roads, drainage features and other constraints.
One of the most common mistakes in early site appraisal is comparing density figures without checking whether they are gross or net. The difference can materially change how a residential scheme is judged.
Gross density uses the full site boundary. It is useful for early land comparison, but can understate the intensity of the actual residential layout where large parts of the site are taken up by open space, drainage, buffers or access.
Net density uses the developable residential area. It is often more useful for understanding how compact the built layout actually feels once non-developable land has been removed.
Density should never be read in isolation, but it can give an early clue about the type of housing layout that may be needed.
Often detached and semi-detached homes, softer edges, larger gardens or more landscape-led layouts.
Commonly a mix of semis, terraces, short runs and modestly compact family housing.
Often terraces, townhouses, compact parking arrangements and more efficient street patterns.
Usually town centre, apartment-led or very compact urban schemes requiring strong design justification.
A calculated density is only the starting point. A professional layout can test whether the number works in real planning, movement, parking and placemaking terms.
Dwellings per hectare, often shortened to dph, measures how many homes are proposed for each hectare of land.
Divide the number of proposed dwellings by the site area in hectares. For example, 85 homes on 2.4 hectares equals about 35 dwellings per hectare.
Gross residential density uses the whole site area, including land that may be used for access, open space, drainage, landscaping and constraints.
Net residential density uses the developable residential part of the site. It usually excludes major open space, strategic roads, drainage features and unusable land.
Net density is usually higher because the calculation area is smaller. The same number of homes divided by a smaller developable area creates a higher dwellings-per-hectare figure.
Many suburban residential schemes sit somewhere around 25–40 dwellings per hectare, but appropriate density depends heavily on local context, planning policy and design quality.
Potentially, yes. More homes can improve GDV, but only if the layout is acceptable, marketable, deliverable and likely to gain planning support.
No. It calculates density only. Planning approval depends on policy, access, highways, drainage, ecology, landscape, design quality and local consultation.
A professional review is useful once you have a site boundary, approximate area and a proposed number of homes. It can test whether the density works as a real layout.
