Housing Need Calculator
How many dwellings an area needs to build each year to house its projected population — from growth, household size, a healthy vacancy rate and the replacement of old stock.
Project the population forward, divide by the persons per household to get the households, add the vacancies a functioning market needs (about 3% of stock) and compare with the dwellings that exist.
How the housing need calculator works
Project the population forward, divide by the persons per household to get the households, add the vacancies a functioning market needs (about 3% of stock) and compare with the dwellings that exist. Spread the shortfall over the years, and add the share of stock demolished or converted each year. Shrinking household size raises the need even with flat population — the quiet driver of housing demand in ageing cities.
Formula: dwellings needed = households_future × (1 + vacancy) − existing + replacement × years; per year = ÷ years
Worked examples
| Inputs | Dwellings needed per year | Note |
|---|---|---|
| 150,000 growing 1.5% a year for 10 years | 1,457 | about 1,400 a year |
| Flat population, shrinking households | 372 | still about 400 a year |
| Fast growth: 3% a year | 848 | about 870 a year |
FAQFrequently asked questions
Why does household size matter so much?
A fall from 2.5 to 2.4 persons per household adds 4% to the dwellings a fixed population needs — in a city of 150,000 that is 2,500 homes, as much as several years of population growth.
What vacancy rate is healthy?
About 3% of stock lets people move, renovate and sell without shortage; under 1.5% rents rise sharply, above 5% suggests oversupply. It applies to the whole stock, so it must be built too.
What is the replacement rate?
Dwellings demolished, converted or lost each year — typically 0.2–0.5% of stock, more in areas with old housing or redevelopment. They must be rebuilt just to stand still.
Does this say where or what type?
No — it is the total. The housing-mix and dwelling-density calculators, and the projected age profile, turn the number into a mix of apartments, townhouses and houses across the area.
Where these figures come from
- UN-Habitat — Urban Indicators Guidelines — density, green space and public space benchmarks
- World Health Organization — Urban green spaces — the 9 m² per person minimum
- ITE — Parking Generation Manual — parking demand rates by land use
- Australian Bureau of Statistics — Regional population — Australia's national statistics agency
Last checked: September 2026. Default per-capita rates are mid-range figures from national statistical agencies and utility reports; every one is an input you should replace with the local figure.