Why Your Petrol Is Getting Cheaper — And 3 Reasons It Won't Last
National average petrol is down 5% to $2.13/L this week — the third straight weekly fall. Three forces are cutting your fuel bill (including one nobody's talking about), and three threats are about to reverse them. Here's what's really driving the price and when to fill up.
The Number That Surprised Drivers This Week
For the first time since the Iran war began in late February, the petrol price board is finally moving in the right direction.
The national average for unleaded hit **$2.13 per litre** in the week to 20 April — a roughly **5% drop** from the March peak and the **third straight weekly fall**. Capital-city averages are down **more than 30 cents** since the excise cut took effect on 1 April, according to ACCC weekly monitoring data.
That's the good news. Here's the caveat: you're still paying about **18% more** than you were in early March, before missiles started flying in the Persian Gulf. Diesel is an even rougher ride — down only 3% off the peak and still hovering around **$3.09/L nationally**, with Sydney metro sites posting $3.19 at some locations.
So what's actually driving the fall? It's not one thing. It's three — and one of them is the quiet mechanism nobody's talking about.
Reason 1: The Excise Cut Is Finally Flushing Through
The halved excise (52.6c/L → **26.3c/L**) took effect at 12:01 AM on 1 April 2026. We wrote [on day one](/blog/fuel-excise-day-one-retailers-slow-pass-savings-2026){:target="_blank"} that retailers would drag their feet — and they did. But three weeks in, stock rotation is doing its job.
High-volume metro servos had already transitioned by mid-April. The 7-Elevens, BPs and Ampols on busy highway corridors refill every 3–4 days, so their cost base reset quickly. Regional independents took longer — some are only now seeing relief — but the ACCC's **$100M maximum penalty** and weekly public monitoring have given the laggards a shove.
Stacking the **4c/L supermarket fuel discount** (Coles/Shell, Woolworths/Ampol) with a top-up $5 purchase at the servo — which doubles the discount to 8c/L — and the 7-Eleven 7-day price lock function means motivated drivers are now seeing **effective prices below $2.00/L** in competitive metro pockets. That was unthinkable a month ago.
Bottom line: the 26.3c/L cut is real, but it's only about **half** of what's driving the fall. The rest is quieter — and more interesting.
Reason 2: The Australian Dollar Is Doing the Heavy Lifting
Here's the headline that didn't make the 6 o'clock news: the **Australian dollar is trading at a 3-year high** against the US dollar.
AUD/USD closed last week around **0.7141** — up from 0.6410 twelve months ago, an **11% annual gain**. Against a basket of Asian currencies where refined fuel is actually traded, the AUD is even stronger.
This matters because Australia imports roughly **90% of its refined petrol and diesel**, and every litre of that product is priced in US dollars on its way out of Singapore, Korea and the Gulf. When the AUD strengthens, the same USD invoice costs fewer AUD to land on an Australian forecourt.
Rule of thumb: **a 1-cent move in AUD/USD is worth 2–3 cents per litre at the bowser**, with a 1–3 week lag. The currency has moved about **7 cents** against the USD since the AUD bottomed in mid-2025. Do the arithmetic — you're looking at roughly **14–20 cents per litre** of relief, most of which is showing up at pumps right now.
Here's the comparison no one's making:
| Driver | Value to the bowser | Status | |---|---|---| | Excise cut (1 Apr) | ~26.3c/L | Flushing through, ~half passed on | | Stronger AUD (12 months) | ~14–20c/L | Landing now, quiet tailwind | | Brent crude off peak | ~8–12c/L | Live; volatile | | Singapore Mogas cooling | ~4–6c/L | Live; benchmark easing |
The Aussie dollar has quietly done **as much work as the excise cut** — and it hasn't cost the Federal Budget a single dollar.
The Quiet Irony: Your Mortgage Pain Is Cheapening Your Fuel
Here's the part that makes it interesting.
The RBA has been hiking the cash rate to beat back sticky domestic inflation — it now sits at **4.10%** after two moves this year, and markets are pricing about a **77% chance of another 25 basis-point hike on 5 May**. Every one of those hikes makes your mortgage more expensive, your rent more expensive, and small business borrowing more expensive.
It also makes the Australian dollar more attractive to global investors chasing yield. Higher AUD interest rates relative to the US, Japan and Europe = more demand for AUD = stronger currency = cheaper imports.
And what's Australia's biggest import by dollar value after medicines? **Refined petroleum.**
So yes — the same RBA policy that's making your home loan painful is quietly making your petrol cheaper. It won't show up in any political talking point, because "we hiked rates to cut the petrol bill" is a terrible slogan. But it's happening. Roughly **4–6 cents** of the last month's price fall is purely currency-driven.
This is the classic monetary transmission mechanism. Textbook stuff. It's just that nobody notices because the headline is always about mortgages.
Reason 3: Brent Crude Is Off Its March Peak
The third driver is the one everyone expected: **crude oil is cooling**.
Brent traded between **$94 and $106 a barrel** last week, closing Wednesday at $104.83. That's still elevated — pre-war Brent was in the high-$60s — but it's **a long way below the $119 March peak** and nowhere near the $166 Dubai spike that panicked markets mid-month.
What's changed:
- The **Strait of Hormuz is partially reopened**. Iran is letting tankers through under an extended ceasefire while US–Iran talks continue (Steve Witkoff and Jared Kushner are flying to Pakistan this weekend for another round). - **Singapore Mogas 95** — the actual benchmark Australian wholesalers price off — has retreated from its 106 Australian-cents-per-litre mid-March peak. - **Demand destruction is real**. Australian and global drivers are burning less fuel after the March panic; retail volumes are below seasonal norms. - The **IEA's 400-million-barrel coordinated release** provided breathing room.
That said, don't confuse "cooling" with "low". Brent at $100+ was a crisis-level price a year ago. Today it's just... normal, because we got used to worse.
The excise cut saves 26c/L. The AUD saves ~15c/L. Brent coming off the peak saves ~10c/L. Stack those and you get the ~50c/L of retail relief we've seen since mid-March.
Now For The Bad News: Three Cliffs Are Coming
Every one of the three forces cutting your fuel bill has an expiry date — and two of them are in the next 60 days.
If you're planning winter road trips, budgeting the household fuel bill, or running a small business that burns diesel, you need to know what's about to change.
Here are the three risks, ranked by how certain they are to bite.
Risk 1: The Excise Cliff on 1 July 2026 (Near-Certain)
On **1 July 2026**, the 26.3c/L excise snaps back to **52.6c/L overnight**. That's a mechanical, legislated event — no ministerial discretion required. It just happens unless the government actively extends it.
The decision is expected at **Budget Night on 12 May 2026**. Extending for another three months would cost the Budget about **$2.55 billion**. Treasurer Jim Chalmers has given no public commitment either way. The political logic points both ways: an extension is popular but fiscally expensive in a cost-of-living election cycle; letting it expire is fiscally responsible but risks a winter price shock.
**Our base case:** A partial extension (maybe 13c/L of relief instead of 26.3c/L), or a three-month extension bolted on with conditions. A clean extension at the full 26.3c/L would surprise to the upside. A hard expiry would be a political gift to the opposition.
**What it means for you:** If 1 July hits without an extension, expect **national average ULP to jump by ~26c/L overnight** and diesel by slightly less. A 65-litre fill goes up ~$17 on day one.
Mark **Monday 12 May** in your calendar. That's the night this year's fuel bill gets decided.
Risk 2: The US–Iran Ceasefire Is Held Together With String
The Middle East ceasefire is the biggest non-scheduled risk on the board.
The current ceasefire has been extended indefinitely, but the Strait of Hormuz is **still not fully reopened**, Iran has already seized two tankers this month, and US–Iran direct talks have stalled. Trump threatened to resume strikes last week before backing off. Witkoff and Kushner are meeting Iranian officials in Pakistan this weekend in what everyone is describing as a "last chance" session.
If those talks collapse and either side escalates, Brent is back at $130+ within a week and Singapore Mogas will spike alongside it. That would wipe out the entire ~10c/L of crude-related relief in a matter of days and probably add another 10c/L on top for good measure.
The tell to watch: **tanker traffic through Hormuz**. Bloomberg and Reuters publish daily counts. When the number drops, crude rises. Australia has only **36 days of petrol reserves** (target: 90) — there is no buffer if the Strait closes hard.
This is the tail risk that could undo everything.
Risk 3: The AUD Could Snap Back
This is the risk nobody is pricing.
The AUD rally has been driven by RBA hawkishness. Two hikes in 2026, another priced for 5 May, and the yield differential with the US Fed is the widest it's been in years. That's what's pulling the currency higher.
But the rally has three ways it could reverse fast:
1. **The RBA pivots dovish.** If Q1 CPI (released 29 April) comes in below 3.2%, the 5 May hike is off the table. Markets would unwind the hawkish trade and the AUD could drop 2–3 cents quickly. 2. **Global risk-off.** The AUD is a classic "risk currency" — it sells off hard when global markets get scared. Any fresh Middle East escalation, a US recession scare, or a China growth wobble would send the AUD lower. 3. **US dollar strength.** If the Fed signals it's back in hiking mode, or if US long-end yields spike, the USD gains across the board and the AUD weakens passively.
A 3-cent AUD/USD reversal would cost about **6–9c/L at the bowser** within three weeks. Combined with even a partial crude re-rally, we could be back above $2.30/L before the excise cliff even arrives.
Watch the **29 April CPI print**. It's the single biggest data point between now and Budget Night.
What To Do Before the Cliff
Tactical advice for the next 60 days:
**1. Fill up now while the window is open.** The current combination of excise cut + stronger AUD + cooler Brent is the cheapest the bowser has been since early February. If your tank is below a quarter, top up — don't wait for a further fall that may not come.
**2. Use FuelCalc for every fill.** Prices are now moving **15–20c/L between servos within the same suburb** as the excise passes through unevenly. [Check live prices at your local servos](/){:target="_blank"} before committing to a fill. The saving on a single tank can exceed the weekly grocery discount.
**3. Stack loyalty programs.** Coles/Shell and Woolworths/Ampol both run 4c/L discounts that double to 8c/L when you add a $5 in-store purchase. 7-Eleven's app lets you lock in the cheapest price within a geographic radius for 7 days — useful if you're about to road trip.
**4. Watch Monday 12 May.** Budget Night is the single most important event between now and winter. If the excise is extended, relax. If it isn't, fill up on 30 June.
**5. Don't stockpile diesel.** Diesel isn't falling as fast as petrol and prices are more volatile week-to-week. If you're a small business burning 200+ litres/week, talk to your supplier about locking a forward rate *after* Budget Night, not before.
**6. Road trip timing matters.** If you're driving Sydney→Melbourne, Brisbane→Cairns, or Perth→Margaret River this winter, May and the first half of June are your cheapest windows. From 1 July onwards, budget an extra ~$15–$20 per fill-up.
The next 60 days are the cheapest petrol you're going to see this year. Use them.
The Bottom Line
Three forces are pulling petrol prices down right now: the excise cut is flushing through, the Aussie dollar is doing quiet work via import parity, and crude is off its peak. Combined, they've pulled the national average back to **$2.13/L** — still elevated, but manageable.
Three forces are about to pull it back up: the **excise cliff on 1 July**, the **fragile US–Iran ceasefire**, and the **risk of an AUD reversal** if the RBA goes dovish or global markets turn risk-off.
The next date that matters is **29 April** (Q1 CPI) — the data point that decides the RBA's May move and therefore the AUD's next leg. Then **5 May** (RBA decision), then **12 May** (Budget Night and the excise extension call). All three happen in the next 17 days.
This isn't a normal fuel cycle. It's a policy-and-currency cycle that just happens to be showing up at the bowser. Track it the way it deserves to be tracked — and [use FuelCalc](/){:target="_blank"} to make sure every litre you buy between now and 1 July is the cheapest one available.
Fill up. Watch Budget Night. Don't get blindsided in July.
Tags: petrol prices, fuel prices Australia, Australian dollar, AUD USD, RBA cash rate, fuel excise cut, excise expiry 1 July, Brent crude, Singapore Mogas 95, Federal Budget 2026, cost of living, fuel crisis 2026