CPI

What is the CPI?

The Consumer Price Index (CPI) provides the official measure of inflation in Australia. The CPI is calculated by the Australian Bureau of Statistics. Movement in the CPI is measured quarterly for the three month periods ending 31 March, 30 June, 30 September and 31 December each year. The CPI figures are normally published around four weeks after the end of the quarter. The CPI is not a percentage but an index number. Any two numbers from the index can be compared to calculate a percentage change.

CPI indexation factor

The CPI indexation factor is determined by comparing two quarters of CPI figures. The more recent of these quarters is known as the reference quarter and the older is known as the base quarter. The CPI number for the reference quarter is divided by the CPI number for the base quarter, rounding the answer to three decimal places.    

Reference and base quarters for CPI

Legislation describes which CPI figures are used as the base and reference quarters. The reference and base quarters vary between different payments, allowances and limits.