If you have read a headline saying Australia's population passed another round number, the figure behind it is almost certainly the estimated resident population, or ERP. The Australian Bureau of Statistics puts Australia's population at 27,921,150 people at 31 March 2026. Knowing how that number is built tells you what it counts, what it deliberately leaves out, and why a second official count can disagree with it without either being wrong.
The official concept: estimated resident population
Australia's official population concept is the Estimated Resident Population, and the official population number is produced by the ABS, according to population.gov.au. The Bureau of Infrastructure and Transport Research Economics (BITRE) describes it the same way: ERP is "the official measure of Australia's population produced by the Australian Bureau of Statistics."
The definition is short but does most of the work: ERP counts people living in Australia for at least 12 of the last 16 months. Three practical points follow from that wording.
- The test is residence, not citizenship, visa status or passport held.
- The window is 16 months rather than 12, so ordinary holidays, work trips and short absences do not push a resident out of the count.
- Physical presence on its own is not the test. Someone visiting Australia for a short stay sits outside ERP even though they are in the country.
National figures are published in the ABS release National, state and territory population, according to population.gov.au.
Two counts, two different questions
The most common source of confusion is that Australia produces more than one population count, and they answer different questions.
| Count | The question it answers | How it is defined | Where it comes from |
|---|---|---|---|
| Estimated resident population (ERP) | Who usually lives in Australia? | People living in Australia for at least 12 of the last 16 months | Produced by the ABS; national figures in National, state and territory population |
| Census count of people in Australia | Who was in the country at that moment? | In Australia at a particular time, regardless of where they usually live | Measured in the Census by the ABS |
That difference matters in practice. A census-night count can include visitors who happened to be in Australia at the time and can exclude residents who were temporarily overseas. ERP applies a residence test across a 16-month window instead. So if two figures disagree, check the concept first before assuming one is a correction of the other.
Why the number keeps moving
ERP is an estimate attached to a reference date, not a fixed fact about the country. The ABS publishes population estimates back to 1981 and projections out to 2066, along with an up-to-the-minute projection of Australia's population.
Practical interpretation:
- Always read the "at" date. A figure quoted without one is not usable for comparison.
- Treat quarterly figures as a series rather than an event. Later releases can restate earlier ones.
- Keep estimates and projections in separate buckets (see below).
BITRE also publishes ERP material for regions and cities, which shows why a single, official national series is useful: different agencies can work from the same base instead of building their own counts.
What the current estimates show about composition
Two ABS figures are worth reading alongside the headline number because they describe change rather than just size:
- At 30 June 2025, Australia's population included 8.8 million people who were born overseas.
- The proportion of Australia's population born outside Australia was 32.0%.
The ABS also tracks longer-run change, reporting that Australia's population increased from 3.8 million in 1901 to 25.7 million in 2021. For composition by birthplace, the ABS maintains a dedicated topic on Australia's population by country of birth.
Estimates are not projections
This is the second most common mix-up. Population Projections, Australia reports that Australia's population in 2022 (26 million) is projected to reach between 34.3 and 45.9 million people by 2071. That is a modelled range built on assumptions about future births, deaths and migration, not a prediction that any particular outcome will occur. A wide range is a feature, not a flaw: it reflects genuine uncertainty about the assumptions.
An estimate describes a past reference date. A projection describes what could happen under stated assumptions. If you are writing about housing, infrastructure or service demand, say which one you are using.
How to check the number yourself
Use this checklist before you quote or rely on a population figure.
- Go to the ABS population statistics page and find the latest release.
- Record the reference date (for example, 31 March 2026) alongside the number.
- Confirm the concept: ERP, census count or projection.
- Confirm the geography: national, state and territory, or a region or city cut.
- Note the release date, and check whether the figure has been revised since first publication.
- For composition questions, use the country-of-birth topic rather than the headline total.
Questions worth verifying
Because these details change, confirm them at the source rather than relying on any summary, including this one:
- What is the currently published ERP, and what is its reference date? (ABS)
- Has that quarter's estimate been revised since it was first released? (ABS methods and release notes)
- Which concept and geography does the figure you are reading actually use?
- If you need a census-based count, which Census is it drawn from, and what was its reference point?
- For regional or city analysis, does BITRE or the ABS publish the cut you need?
Next steps
Bookmark the ABS population statistics page as your primary source and population.gov.au for plain-language explanations of how population measurement works. If you use regional figures, add the BITRE estimated resident population resource to the same list. When you cite a number, cite the concept, the geography and the reference date together — that is what makes a population figure reusable and checkable by someone else.
Readers who are tracking population growth because of what it may mean for housing demand can see how lending criteria work in our home loan guide at /money/home-loans/.
General information only
This article is general information about official statistics. It is not legal, tax, migration, credit or financial advice, and it does not predict any individual outcome. Population figures are revised and re-dated over time, so verify the current number and its reference date directly with the ABS or population.gov.au before relying on it.