What a price cycle is
In a city with a price cycle, unleaded prices do not drift up and down with costs. They move in a saw-tooth. On one day, usually led by one of the large chains, prices across the city jump by a large amount in a matter of hours. Over the following days or weeks, servos undercut each other a cent or two at a time and prices slide back down, until the margin is close to nothing. Then they jump again.
The jump is called a restoration, because it restores the retail margin. The slow fall is the undercutting phase. The wholesale price, meanwhile, moves smoothly with international prices and has nothing to do with the timing of either.
At the bottom of a cycle the margin over wholesale can be only a few cents. Just after a restoration it is often 30c a litre or more. Same servo, same fuel, same week.
Which cities have them, and how long they run
The ACCC, which monitors fuel prices for the federal government, tracks cycles in the five largest cities. Its figures for recent years put the average cycle at roughly the following.
| City | Typical cycle | What that means |
|---|---|---|
| Perth | About 1 week | A weekly rhythm, lowest early in the week |
| Adelaide | About 2½ weeks | Two or three restorations a month |
| Sydney | About 5 weeks | Long, slow falls, then a sharp jump |
| Melbourne | About 6 weeks | Long cycle, now under Victoria's new daily cap rule |
| Brisbane | About 6–7 weeks | The longest of the five |
Averages from the ACCC's petrol price cycle reporting. Individual cycles are often shorter or longer.
Canberra, Hobart, Darwin and most regional towns do not have regular cycles. Prices there move more slowly and track costs more directly, which is partly why they tend to sit higher for longer. Diesel does not cycle anywhere. It follows the wholesale price with a fairly steady margin.
Perth is different, by design
Western Australia's FuelWatch scheme requires every servo to tell the government by 2pm what it will charge tomorrow, and to hold that price for 24 hours from 6am. Tomorrow's prices are published each afternoon. That rule has pinned Perth's cycle to a week, and for years the pattern has been cheapest on Tuesday and dearest from Wednesday. It is the only capital where a day of the week is a reliable guide, and even there it is worth checking FuelWatch rather than assuming.
Victoria adopted a similar rule through Servo Saver. Retailers set tomorrow's maximum price by 2pm, it is published by 4pm, and prices can fall during the day but not rise above that cap. The Northern Territory moved to next-day prices in April 2026. Over time these rules tend to make cycles shorter and more predictable.
How to tell where you are in the cycle
You do not need to track the cycle for weeks. You need two numbers, the price on the sign and the wholesale price for your city, which is on each city page and updated every weekday.
- Within about 5 to 10c of wholesale means you are near the bottom. Fill up, and fill the tank.
- 10 to 15c above wholesale is normal. Fill up if you need to.
- 25c or more above wholesale, especially if it was much lower a few days ago, means a restoration has just happened. Buy only what you need and wait for the slide, or look for a servo that has not raised its price yet.
The state price apps help with the last step. When a restoration starts, it spreads across a city over a day or so, and the servos that have not yet moved are easy to spot on a map. Our guide to the state apps lists the official one for each state.
When cycles break down
Cycles depend on wholesale prices being fairly steady, so that the margin is what moves. When wholesale prices rise quickly, as they did in March and again in September 2026, retailers raise prices to keep up with their costs rather than waiting for the next restoration, and the saw-tooth becomes irregular. National wholesale petrol rose 35c a litre during September 2026 alone. In a month like that, the bottom of the cycle can be higher than the top of the last one, and the useful question is simply how far your servo is above today's wholesale price.
How much it is worth
If the difference between buying at the bottom and buying just after a restoration is 25c a litre, and you buy 50 litres a week, timing your fill saves about $12 each time. Most people will not hit the bottom every time, but even catching it half the time is worth around $300 a year. That is more than most discount dockets, and you can stack the two.
Where these figures come from
Wholesale prices are the terminal gate prices published each weekday by the Australian Institute of Petroleum, which we hold back to 2004. The national figure is AIP's own average where it has published one, and our weighted calculation in between, which matches AIP's to within 0.1c. Oil and currency prices are delayed market closes. Excise rates are the ATO's. We check every figure against that data before publishing and correct mistakes in the update log. Spotted one? Email hello@thepetrolprice.com.