Monthly CPI Indicator

The Monthly Consumer Price Index (CPI) Indicator, published by the Australian Bureau of Statistics (ABS), measures monthly price change for metropolitan households. It belongs to the Consumer Price Index program and reuses available quarterly CPI data and methods consistent with that measure. Coverage is national, as a weighted average of the 8 capital cities, using web-scraped, online, telephone and administrative prices including scanner data. It is a retailer price collection with no household sample, not a replacement for the quarterly CPI, the principal measure of household inflation.

Prices are collected through the reference month at set intervals, with monthly items priced monthly and quarterly items in the same month each quarter. Results appear about 4 weeks after month end at 11:30am Sydney time, except November data, which appears in January. Each release shows All-groups annual and monthly change, 11 groups, analytical series, goods and services, tradables and non-tradables, tables, charts and a media release.

The indicator may be revised for 1 to 2 months as fuller data arrives. It may also be revised for 12 months when a series moves to monthly measurement, while the quarterly CPI is revised only in exceptional cases. A rise means higher household inflation against the Reserve Bank of Australia's 2% to 3% aim, and ABS gives no trading signal.

The 11-group basket below, combined by weights, drives the headline.

• Food and non-alcoholic beverages, Alcohol and tobacco: groceries, fresh produce, meals out, beer, wine, spirits and cigarettes.
• Housing: rents, new homes for owner-occupiers, electricity and gas.
• Transport: car fuel, cars and public transport.
• Clothing and footwear, Furnishings, household equipment and services: garments, shoes, furniture, appliances and household services.
• Communication, Recreation and culture: phone devices and services, holiday travel, lodging, audio-visual and sport.
• Health, Education, Insurance and financial services: medical, dental, pharmaceuticals, school and university fees, insurance premiums and financial charges.

In the 12 months to August 2024, released 25 September 2024, it rose 2.7%, down from 3.5% in July, the lowest since August 2021. Housing rose 2.6%, Food 3.4% and Alcohol and tobacco 6.6%, partly offset by Transport at -1.1%, while car fuel fell 7.6% from August 2023. Electricity fell a record 17.9% on Commonwealth Energy Bill Relief Fund and state rebates.

Excluding volatile items and holiday travel, inflation was 3.0% and trimmed mean 3.4%, after 3.7% and 3.8% in July, a two-and-a-half-year low. Headline 2.7% therefore sat below trend pressure still above the 2% to 3% aim.

1. Collect: Prices come from web scraping, online, phone and scanner data and administrative records, priced monthly, quarterly or yearly by design. Monthly prices cover 50% of basket weight: 68% in month 1, 79% in month 2 and 77% in month 3 of each quarter.
2. Carry-forward imputation: For items not priced that month, assume no change and reuse the prior price.
3. Weighted aggregation: Combine new and reused prices by the 87 class weights, scaled to a base of 100.0. Weights update yearly from household spending surveys and national accounts.
4. Movement math: Point change is later index minus earlier index, and % change divides that gap by the earlier index, using rounded one-decimal indexes. Publisher example: July 2022 at 114.2 minus June 2022 at 113.5 is 0.7 points, or 0.7 divided by 113.5 times 100, which is 0.6%. Annually, 114.2 minus July 2021 at 106.7 is 7.5 points, or 7.5 divided by 106.7 times 100, which is 7.0%.
5. Seasonal adjustment: Re-estimate seasonal and calendar factors monthly from full history and rebuild the total from adjusted and unadjusted components. Prior month and same month a year earlier shift most.
6. Annual trimmed mean: Rank classes by seasonally adjusted monthly change, trim top and bottom 15%, then average middle 70% of year-ended moves by prior-month weight.