3.4.3 CPI indexation for cost of living
Context
Court orders and court registered agreements or child support agreements often contain clauses providing for an annual adjustment of the amount payable in accordance with changes in the CPI.
Treatment of CPI clauses
If a court order or court registered agreement provides for a review of the amount payable on a specified date, the arrival of that date is an affecting event (CSRC Act section 4(1)).
An order or child support agreement with a CPI clause will generally state the date on which the comparison is to be made and the particular figures to be used (for example, the weighted average of CPI figures in all capital cities or a specific capital city). Where an order simply refers to CPI, but not a specific measure of it, the Registrar will use the weighted average of CPI in all capital cities from the corresponding quarter of the previous year. The ABS publishes these figures.
For historical CPI values please see topic 2.4.14.
CPI figures
The relevant CPI figures for the most recent year are provided below (ABS Consumer Price Index, December Quarter 2024).
| Period | Sydney | Melbourne | Brisbane | Adelaide | Perth | Hobart | Darwin | Canberra | Weighted average |
|---|---|---|---|---|---|---|---|---|---|
| Dec 2024 | 139.7 | 139.5 | 140.2 | 140.5 | 137.9 | 138.9 | 133.7 | 137.3 | 139.4 |
| Sep 2024 | 139.8 | 139.3 | 139.4 | 140.6 | 137.0 | 136.8 | 133.8 | 137.2 | 139.1 |
| Jun 2024 | 139.1 | 138.4 | 140.6 | 139.9 | 137.6 | 138.3 | 133.6 | 136.8 | 138.8 |
| Mar 2024 | 137.7 | 137.5 | 139.2 | 138.1 | 134.8 | 138.1 | 132.4 | 135.6 | 137.4 |
| Dec 2023 | 136.4 | 136.1 | 137.7 | 137.1 | 134.0 | 136.8 | 131.5 | 134.3 | 136.1 |
Where a court order or agreement includes a clause providing for an annual adjustment of the amount payable in accordance with changes in CPI, the ABS data will be used to calculate the new amount payable. The table above should be used for any adjustments that are required to use September 2012 CPI indexation figures onwards.
The formula used to apply the CPI inflation factor and calculate the new amount payable is:
- Latest quarter index ÷ Earliest quarter index × previous entitlement
Example: A court order provides for the periodic amount of $100 per week to be inflated by the September Sydney CPI, to take effect from 1 January each year.
September 2023 quarter CPI for Sydney - 135.8
September 2024 quarter CPI for Sydney - 139.8
139.8 ÷ 135.8 × $100 = $102.95
The new periodic amount payable under the court order will be $102.95 per week starting from 1 January 2025.
CPI re-reference
In September 2012, the ABS re-referenced the CPI figures, setting the index base to 100.0 for the reference period 2011-12. The ABS also published conversion factors to allow the figures using the new index reference period to be converted to figures that are consistent with figures published before the re-referencing.
The conversion factors are:
| Sydney | Melbourne | Brisbane | Adelaide | Perth | Hobart | Darwin | Canberra | Weighted average |
|---|---|---|---|---|---|---|---|---|
| 0.5584 | 0.5649 | 0.5409 | 0.5447 | 0.5572 | 0.5614 | 0.5654 | 0.5550 | 0.5567 |