The published CPI prices a basket averaged over every household in the country: one that rents and owns, drives and takes the bus, smokes a little. Answer eight questions and the index is rebuilt from the 2025 weighting pattern — the same chain Laspeyres arithmetic the ABS uses, over your basket instead of the average one.
Weights come from the ABS 2025 weighting pattern, which is price-updated to Dec 2024. Index numbers can only be aggregated with the weights of their own link period, so the series starts there and runs to Aug 2026. Selecting every category reproduces the published CPI to within 0.01 index points.
