How petrol price cycles work in Australia

What's a price cycle?

In Sydney, Melbourne, Brisbane, Adelaide, and Perth, retail petrol prices move in waves. Prices drop slowly over several weeks, then spike sharply — sometimes overnight — back toward a peak. The cycle then repeats. This pattern has been documented by the ACCC in its quarterly fuel market reports for more than two decades.

Why does it happen?

Price cycles aren't driven by wholesale costs or the global oil market. The ACCC has concluded that cycles are a deliberate retailer strategy: retailers compete gradually on price until margins get too thin, then one major chain “restores” prices to a higher level and the others follow within days. Wholesale prices might only move a few cents across an entire cycle; retail prices can swing 30–40 cents.

In other words: the cycle is a margin-rebuilding mechanism, not a reflection of what it actually costs to put fuel in the tanker.

Cycle length by city

Cycles vary by city and change over time. Recent ACCC reporting suggests cycles currently run roughly:

• Sydney: 4–6 weeks
• Melbourne: 4–6 weeks
• Brisbane: 4–5 weeks
• Adelaide: 2–3 weeks
• Perth: weekly (reset every Tuesday)

Perth is unique — Western Australia's FuelWatch laws require stations to publish the next day's price by 2pm and hold it for 24 hours. Prices almost always spike on Wednesday or Thursday and decline slowly through the weekend into Tuesday. Tuesday is consistently the cheapest day to fill up in Perth.

How to use the cycle to save

If you can time your fills, the bottom of the cycle is typically 20–30 cents per litre cheaper than the peak. For a 60-litre tank that's $12–18 saved per fill. Over a year of weekly fills, that's $600–900 — real money, for a small change in habit.

Signs you're near the bottom of a cycle: brand-to-brand variation narrows (7-Eleven, BP, Shell all showing similar prices), and weekly average prices have been declining for two to three weeks. Signs a spike is imminent: one major chain raises prices 20 cents or more overnight — expect others to follow within 48 hours. If you spot that, fill up today.

Regional petrol prices are different

Outside the five capital cities, most regional markets don't follow a cycle. Prices tend to sit at a flat premium to the wholesale rate, with smaller fluctuations driven by delivery costs and local competition. There's usually no benefit to waiting — fill up when you need to.

Refuelr's price cycle card shows you where each capital city sits in its current cycle, based on rolling averages across the city's stations. In supported regions it will tell you whether prices are near the bottom, mid-cycle, or climbing.