Excise Cut Day 4: Petrol Crosses Full Pass-Through, Diesel Goes Backwards
Four days after the excise was halved, U91 has crossed 100% pass-through nationally at 101.5%. Six of eight states are above 98%. But diesel has gone backwards — dropping from 59% to 53% pass-through as wholesale costs bite.
Four days into the fuel excise cut, U91 unleaded has crossed full pass-through.
The national average has dropped 26.7 cents per litre from the day before the cut — from 259.0 to 232.3 c/L. That's 101.5% of the 26.3 cent excise reduction. On a 65-litre tank, that's $17.36 in savings.
Every petrol grade is now above 100%. The petrol story is done.
Diesel is a different matter. It's gone backwards.
The national picture — Day 1 through Day 4
| Fuel | Before cut (c/L) | Day 1 (c/L) | Day 2 (c/L) | Day 3 (c/L) | Day 4 (c/L) | Total drop | Pass-through |
|---|---|---|---|---|---|---|---|
| U91 | 259.0 | 242.0 | 236.5 | 233.5 | 232.3 | 26.7 | 101.5% |
| E10 | 254.5 | 234.5 | 229.6 | 226.7 | 225.4 | 29.1 | 110.6% |
| U95 | 274.0 | 254.9 | 249.8 | 246.4 | 245.4 | 28.6 | 108.7% |
| U98 | 282.6 | 264.4 | 259.1 | 255.8 | 254.7 | 27.9 | 106.1% |
The trajectory has been steady: 65% on Day 1, 86% on Day 2, 97% on Day 3, and now 101.5% on Day 4. E10 and the premium grades crossed 100% a day earlier — U91 was the last to get there.
E10 is now the highest pass-through fuel at 110.6%. The above-100% figures aren't stations overcompensating — they reflect the natural price cycle. States that were near their cycle peak when the cut landed have seen the cycle's downswing stack on top of the excise reduction.
Diesel has gone backwards
This is the headline for diesel: prices went up overnight.
| Fuel | Before cut (c/L) | Day 1 | Day 2 | Day 3 | Day 4 | Total drop | Pass-through |
|---|---|---|---|---|---|---|---|
| Diesel | 323.6 | 312.2 | 311.0 | 311.1 | 312.2 | 11.4 | 43.3% |
| Premium Diesel | 325.1 | 310.1 | 308.7 | 306.2 | 308.5 | 16.6 | 63.1% |
| Diesel Combined | 324.3 | 311.2 | 309.9 | 308.7 | 310.4 | 13.9 | 52.9% |
Diesel Combined rose from 308.7 c/L on Day 3 to 310.4 c/L — pass-through has dropped from 59.3% to 52.9%.
Standard diesel is back where it started on Day 1: 312.2 c/L. Three days of progress erased in 24 hours.
Premium diesel rose too, from 306.2 to 308.5 — still the better performer at 63.1%, but moving in the wrong direction.
Global diesel wholesale costs are the problem. The excise cut is pulling prices down, but rising wholesale costs are now actively pushing them back up and winning. The result: Australian diesel drivers are seeing barely half the benefit that petrol drivers are getting.
State by state
Here's how each state and territory is tracking on U91 unleaded, compared to the day before the cut (31 March):
| State | Before cut (c/L) | Day 1 (c/L) | Day 2 (c/L) | Day 3 (c/L) | Day 4 (c/L) | Total drop (c/L) | Pass-through |
|---|---|---|---|---|---|---|---|
| ACT | 258.0 | 234.5 | 229.4 | 225.4 | 224.7 | 33.3 | 126.6% |
| SA | 262.0 | 239.2 | 236.5 | 232.4 | 231.8 | 30.2 | 114.8% |
| VIC | 258.8 | 239.8 | 234.4 | 231.7 | 231.3 | 27.5 | 104.6% |
| TAS | 259.4 | 237.8 | 235.2 | 233.1 | 232.2 | 27.2 | 103.4% |
| QLD | 259.2 | 240.7 | 235.9 | 233.8 | 233.0 | 26.2 | 99.6% |
| WA | 255.6 | 249.3 | 237.0 | 232.4 | 229.6 | 26.0 | 98.9% |
| NSW | 258.9 | 243.1 | 238.2 | 235.0 | 233.3 | 25.6 | 97.3% |
| NT | 269.6 | 253.3 | 252.2 | 249.3 | 249.3 | 20.3 | 77.2% |
The big picture
Six of eight states and territories are now above 98% pass-through. The excise cut has reached petrol pumps almost everywhere.
ACT continues to lead at 126.6% — a 33.3 cent drop, or $21.65 less on a 65-litre tank compared to four days ago. With only 57 stations, the ACT is a small market, but the consistency is clear.
South Australia is at 114.8%, with a 30.2 cent drop. SA has been above 85% since Day 1 and never looked back.
Victoria (104.6%) and Tasmania (103.4%) have both comfortably cleared full pass-through. VIC's regulated daily price caps likely helped accelerate the adjustment.
Approaching the line
Queensland (99.6%) and Western Australia (98.9%) are essentially at full pass-through — fractions of a cent away. WA started slowest of all states at 24% on Day 1 due to FuelWatch's next-day pricing cycle, but has caught up impressively.
NSW is at 97.3% — solid progress from 60% on Day 1. NSW's 1,957 stations make it the second-largest sample, so this figure is robust.
The outlier
Northern Territory is at 77.2% and hasn't moved since Day 3 (249.3 c/L both days). The NT's smaller market, higher baseline costs, and less competitive pressure mean it's tracking behind the rest of the country. With only 84 stations — many in remote communities — the NT was always going to be the slowest to adjust.
The 32c/L question
States and territories have agreed to fund a further 5.7c/L excise cut, bringing the total reduction to 32c/L. That additional cut hasn't visibly reached pump prices yet — if it had, we'd see broader movement in diesel too.
All pass-through figures in this series are measured against the original 26.3c/L cut. Once the additional 5.7c/L is confirmed in pump prices, we'll shift to measuring against the full 32c/L benchmark.
What happens next
The petrol story is essentially complete. U91 has crossed full pass-through nationally, and every state except NT is above 97%. The next question is whether prices settle at these levels or whether the natural cycle pushes them back up.
Diesel is the concern. Pass-through has gone backwards for the first time since the cut. The ACCC's enhanced $100 million penalty regime is focused on exactly this scenario — retailers absorbing the excise cut into margins rather than passing it to consumers. But global wholesale costs are a legitimate headwind that enforcement alone can't fix.
We'll keep tracking this:
- Day 7 (7 April) — the one-week picture
- Day 14 (14 April) — two-week progress report
- Day 30 (1 May) — the monthly report card
In the meantime, use BowserBuddy to find the cheapest fuel near you. Even with petrol past full pass-through nationally, there's still a 20+ cent spread between the cheapest and dearest station in most areas.
How we calculated this
This analysis uses BowserBuddy's own price tracking data across all eight states and territories. For each station and fuel type, we take the latest known price as of end of day, then compute a station-count-weighted average at the state and national level. This captures the full market — every active station, not just those that changed prices on a given day.
Comparison period: All figures are compared to a full-market snapshot on March 31 (the last full day before the cut took effect). Day 1 through Day 3 figures are also shown to illustrate the daily progression.
Pass-through percentage: Calculated as the price drop divided by 26.3 c/L (the ex-GST excise cut). Pass-through above 100% is possible when the excise cut coincides with a natural price cycle decline. All figures in this post measure against the original 26.3c/L cut, not the expanded 32c/L.
What's excluded: Closed stations, out-of-stock prices, suspected reporting errors, and prices outside reasonable bounds are all filtered before averaging. Prices older than 14 days are excluded as stale. For full details on our data quality approach, see the Data Transparency section on our prices dashboard.
Diesel Combined is a station-count-weighted blend of standard Diesel and Premium Diesel — reflecting the fact that most stations sell one or the other, and drivers take what's available.
Sample sizes: Today's national averages are based on approximately 6,870 U91 price reports and 8,770 diesel price reports across all eight states and territories.