When should I buy petrol in my city?
A one-look answer for regular unleaded in Australia’s five largest cities: where the ACCC buying tip sits in the petrol price cycle, and what that means for filling up. This is a guide, not a forecast of cents or of the cheap day.
Buying tips last updated (19 days ago) — ACCC weekday label “Monday”, transcribed 2026-10-06. This snapshot is older than the 7-day tip cadence. Treat the phase labels as out of date until the next transcription. ACCC petrol price cycles.
Buying tips paused: the last ACCC tip we transcribed is from (19 days ago), older than our 7-day limit. See the ACCC page for today’s tip.
Diesel does not cycle
Retail diesel (and automotive LPG) prices do not move in petrol price cycles. The ACCC does not publish diesel buying tips or a diesel phase.
The five-city diesel average on 30 September 2026 was $2.83/L (283.3 cpl). That is a weekly average from the ACCC monitoring report, not a phase label. Shop around on a fuel-price app the same way you would for petrol; do not wait for a diesel cycle that does not exist.
| City | Average | Phase |
|---|---|---|
| Sydney | 281.6 cpl | None — diesel does not cycle |
| Melbourne | 283.9 cpl | None — diesel does not cycle |
| Brisbane | 287.0 cpl | None — diesel does not cycle |
| Adelaide | 288.5 cpl | None — diesel does not cycle |
| Perth | 275.6 cpl | None — diesel does not cycle |
| 5 largest cities | 283.3 cpl | None |
How to read this
The ACCC publishes buying tips for regular unleaded in Sydney, Melbourne, Brisbane, Adelaide and Perth at least Monday, Wednesday and Friday around midday. We transcribe those tips and map the language to one of five phases: climbing, near peak, falling, near low, or plateau. The phase is a CalcFuel label for ACCC wording. It is not a prediction of the next peak, the next trough, or a price in cents per litre.
Cycles vary from cycle to cycle and by suburb. ACCC says to use the tips as a guide only. When a tip says prices have increased, or that cycles are disrupted, we use climbing or plateau — we do not invent a cheap day. Canberra, Hobart, Darwin and most regional towns do not have petrol price cycles, so they are not on this page.
Since late February 2026 the ACCC has noted that petrol price cycles have mostly not occurred in Sydney, Melbourne, Brisbane and Adelaide. That is why a city can sit in climbing without a named trough. Perth still often moves on a shorter weekly pattern; the live tip, not the 2025 average length, is what the card follows.
Across all fuels, ACCC finds that shopping around with a state price app still saves money: FuelCheck in NSW, FuelWatch in WA, and the other apps listed on the ACCC cycle page. A city average is not the price on your corner.
Source and limits
- ACCC, Petrol price cycles in the 5 largest cities — buying tips last labelled Monday 5 October 2026. Tips apply to regular unleaded and may also apply to PULP95, PULP98 and E10 because those grades tend to move together.
- Australian fuel prices by city — weekly unleaded and diesel averages from the ACCC thirtieth weekly report, prices to 30 September 2026. That snapshot answers “what did it cost?” This page answers “where is the cycle?”
- In-repo steps, including the tip-to-phase table and the 7-day stale rule, are in
docs/accc-cycle-tips-refresh.md. A build check fails when the oldest tip is 7 days old or older (override withCYCLE_TIPS_ALLOW_STALE=1). There is no auto-scrape.
Cost the fill, not just the phase
- Trip fuel cost calculator — a specific drive at this week’s prices.
- Fuel budget planner — weekly and annual household spend.
- Commute fuel cost calculator — what a longer drive to work costs in fuel.
- Evergreen cycle guide — background only. Live phase labels live on this page.