Methodology: Australia

Official data verified · CPI (ABS) · Annual average · Not seasonally adjusted · Data through September 2026 (fetched 2026-11-02) · All groups CPI, weighted average of eight capital cities (6401.0)

The data

All Australian figures come from the Consumer Price Index published by Australian Bureau of Statistics (All groups CPI, weighted average of eight capital cities (6401.0); base period 2011-12=100). ABS data are published under a Creative Commons Attribution 4.0 licence. This site is not affiliated with Australian Bureau of Statistics.

Basis

Calculations use the original (not seasonally adjusted) index, as published. Australia's CPI was a quarterly index from 1948 to 2025 (annual averages here are the mean of four quarters). The ABS now publishes a complete monthly CPI (monthly values from April 2024); the monthly series is published on a different reference base and has been linked to the quarterly series' 2011-12=100 base using the 2024–2025 overlap, where both are published — linking rescales levels only and never changes growth rates. The two bases are never mixed silently: every page states which basis its annual average uses.

The formula

Adjusted amount = amount × (index at end ÷ index at start). Formula v1.0 — annual-average CPI, NSA (per-country basis on each methodology page). Year pages compare annual averages (the mean of a year's published values); the current year's average covers only the periods published so far and is labeled partial. The change in the price level and the change in purchasing power are stated as two separate numbers, because they are not the same: if prices rise 100%, purchasing power falls 50%.

See also the general methodology and the data updates log.