Best day to buy petrol in Australia (2026)

There is no fixed cheapest day for petrol.

By the FuelRadar teamUpdated 23 October 20262 min read

Is one weekday cheaper in each capital? (Unleaded 91)

Each day is compared with the average of the seven days around it, so a rising or falling market cannot make one weekday look cheaper. A capital gets a named day only with a gap of at least 2 c/L and the same low day in most of its full weeks.

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capitals with a reliably cheaper weekday

Sydney
No consistent cheap day
1. Monday −0.2 c/L
2. Tuesday +0.3 c/L
3. Wednesday +0.2 c/L
4. Thursday +0.5 c/L
5. Friday +0.2 c/L
6. Saturday −0.1 c/L
7. Sunday −0.3 c/L
Melbourne
No consistent cheap day
1. Monday −0.3 c/L
2. Tuesday −0.9 c/L
3. Wednesday −0.3 c/L
4. Thursday +0.9 c/L
5. Friday +0.9 c/L
6. Saturday 0.0 c/L
7. Sunday +0.2 c/L
Brisbane
No consistent cheap day
1. Monday −0.1 c/L
2. Tuesday +0.1 c/L
3. Wednesday +0.2 c/L
4. Thursday +0.4 c/L
5. Friday +0.2 c/L
6. Saturday 0.0 c/L
7. Sunday −0.3 c/L
Perth
Wednesday usually cheapest
1. Monday −2.0 c/L
2. Tuesday −2.8 c/L
3. Wednesday −6.4 c/L
4. Thursday +7.6 c/L
5. Friday +4.5 c/L
6. Saturday +1.2 c/L
7. Sunday −1.3 c/L
Wednesday was the lowest day in 10 of 11 full weeks, 6.4 c/L under its weekly average. Thursday was the highest in 11 of 11. Full weeks to 23 Oct 2026.
Adelaide
No consistent cheap day
1. Monday +0.1 c/L
2. Tuesday +0.3 c/L
3. Wednesday 0.0 c/L
4. Thursday +0.1 c/L
5. Friday +0.2 c/L
6. Saturday +0.1 c/L
7. Sunday −0.3 c/L
Canberra
No consistent cheap day
1. Monday −0.5 c/L
2. Tuesday +0.5 c/L
3. Wednesday +0.4 c/L
4. Thursday +0.4 c/L
5. Friday 0.0 c/L
6. Saturday +0.2 c/L
7. Sunday −0.4 c/L
Darwin
No consistent cheap day
1. Monday −0.6 c/L
2. Tuesday −0.2 c/L
3. Wednesday +0.3 c/L
4. Thursday +0.4 c/L
5. Friday +0.1 c/L
6. Saturday +0.4 c/L
7. Sunday +0.1 c/L
Hobart
No consistent cheap day
1. Monday 0.0 c/L
2. Tuesday +0.1 c/L
3. Wednesday 0.0 c/L
4. Thursday +0.2 c/L
5. Friday +0.3 c/L
6. Saturday +0.1 c/L
7. Sunday −0.4 c/L

No weekday was the low in most full weeks in Sydney, Melbourne, Brisbane, Adelaide, Canberra, Darwin and Hobart once the overall price movement is removed. Each figure is that weekday's average gap from its week, in c/L. Based on reported daily Unleaded 91 city averages over the last 90 days, full weeks to 22 Oct 2026. A weekday pattern can change, so check the current cycle and nearby station reports before a large fill.

Is there a cheapest day to buy petrol?

There is no fixed national cheapest day. Sydney, Melbourne, Brisbane and Adelaide have multi-week cycles whose start and duration change over time. Perth currently has a seven-day unleaded petrol cycle, but the useful check is still the notified price at the stations you can reach.

Use the current cycle, not a weekday rule

A retail petrol cycle usually rises over a short period and then falls more gradually. The ACCC reported that average cycle lengths in 2025 ranged from about one week in Perth to about six and a half weeks in Brisbane. That makes old advice such as “always buy on Tuesday” unreliable outside a specific current market pattern.

Current guidance by city

City	2025 average cycle length	Useful check
Sydney	About 5 weeks	Current ACCC buying tip and nearby station reports.
Melbourne	About 6 weeks	Current cycle position rather than a fixed day.
Brisbane	About 6.5 weeks	Current cycle chart and local station spread.
Adelaide	About 2.5 weeks	Whether the current market is rising or easing.
Perth	About 1 week	FuelWatch prices for today and tomorrow.

How to check before a fill

Choose the exact fuel grade your vehicle uses.
Check the current city cycle or buying tip.
Compare nearby service stations by reported price, distance and update time.
If prices have started rising, check whether another nearby retailer has not moved yet.
Confirm the final price at the bowser.

Perth and Western Australia

FuelWatch requires covered retailers to notify prices for the next day and hold that price from 6am for 24 hours. Tomorrow's prices are available after 2:30pm. Compare today and tomorrow, then choose a station that fits your route. The current seven-day cycle applies to unleaded petrol, not diesel or LPG.

How much does a price gap change the tank cost?

A 15c/L difference changes a 50-litre fill by $7.50. A 20c/L difference changes a 60-litre fill by $12. Compare that gross saving with the extra distance before travelling across town.

Official buying tips

The ACCC petrol price-cycle page publishes current buying tips and charts for the five largest cities. Western Australian drivers can check FuelWatch for today and tomorrow prices.

Common questions

What is the cheapest day to buy petrol?

There is no dependable national cheapest weekday. Use the current ACCC buying tip or local cycle chart, then compare station reports for your fuel grade.

When do petrol prices go up?

The timing changes by city and cycle. Retail prices can rise over a short period and then fall more gradually, so check the current chart rather than an old weekday rule.

How do I check tomorrow's petrol prices in Perth?

FuelWatch publishes tomorrow's notified prices after 2:30pm. Covered retailers must hold the notified price from 6am for 24 hours.