⏳ 17 days remaining as of 13 June 2026. The 2025–26 financial year ends at 11:59pm on 30 June 2026. Several of the moves below need 3–5 business days to clear — the practical deadline for super contributions and prepaid expenses is closer to 23 June 2026. Past that, the saving is gone for 12 months.
Sarah is 34, a senior analyst in Melbourne earning $112,000. Her mortgage repayments rose $280 a month after the RBA's May 2026 hike to 4.35%. Her grocery bill is up 18% over two years. Her fuel bill jumped 32.8% in March when conflict in the Middle East spiked global oil — even after the Albanese government halved the fuel excise on 1 April 2026 to soften the blow.
And yet, in the last weeks of June 2026, Sarah is on track to lose $3,840 more than she has to. Not to inflation. Not to the RBA. To five EOFY mistakes Australians make every year — and that are uniquely expensive this year because of where the economic cycle sits.
With headline inflation forecast to peak at 4.8% in the June quarter (RBA Statement on Monetary Policy, May 2026), Roy Morgan projecting 1.6 million Australians at mortgage stress, and the fuel excise cut expiring at the same moment as the tax year, June 2026 is the most expensive month in recent memory to leave EOFY admin to "after the weekend." Here are the five mistakes — ranked by dollar value, with the date each one expires.
Mistake 1 — Letting the 2020–21 Super Cap Expire (Up to $8,000 in Tax Lost)
The carry-forward concessional contribution rule lets Australians with a total super balance under $500,000 on 30 June 2025 use unused cap room from the previous 5 financial years. The cap for 2020–21 was $25,000. Any portion you did not use that year is sitting in your ATO file right now — and at midnight on 30 June 2026, it expires permanently.
There is no extension. No hardship clause. No "I'll catch up next year." Five years is the window, and 2020–21 falls off the back of that window the moment the financial year ticks over.
The dollar value: Sarah's 2020–21 unused cap is $17,210 (she was on $82k earning $7,790 of employer super at the 9.5% rate of the time, leaving $17,210 unused). If she makes a $17,210 personal deductible contribution before 23 June 2026 and lodges a valid s290-170 notice of intent, her marginal tax saving is approximately $5,508 (32% Stage 3 marginal rate plus 2% Medicare on the deducted amount, minus 15% contributions tax inside super). She ends the year with $14,628 more in super and around $5,500 less in tax.
For an Australian on the 37% bracket ($135,001–$190,000) with the same $17,210 unused cap, the saving is around $6,710. At the 45% top bracket the saving is up to $8,260 before Division 293 considerations.
Mistake 2 — Ignoring That the Fuel Excise Relief Expires on 30 June
This one is not a "tax mistake" in the traditional sense — but it is a 30 June dollar event that almost no Australian is planning for. On 1 April 2026, the Albanese government halved the fuel excise on petrol and diesel for three months to soften the cost-of-living spike. That relief reduced the price at the pump by approximately 26.3 cents per litre.
At midnight on 30 June 2026, the relief ends. From 1 July 2026, the full fuel excise rate is reinstated. The forecourt sign moves up by 26 cents overnight — and that is on top of the global oil price level set by whatever the Middle East and OPEC+ are doing at that moment.
The dollar value: For a household driving 16,000 km per year in a vehicle averaging 9L/100km (1,440 L annual fuel), the post-30-June rate increase costs around $379 per year. For a tradie covering 30,000 km on company vehicles, it is approximately $710 in extra running cost. For workers using the cents-per-km method to claim a work vehicle deduction (88c/km for 2025–26, up to 5,000 km), the deduction rate stays the same — but your out-of-pocket fuel bill rises, so the net saving from each claimable kilometre quietly shrinks.
Mistake 3 — Initiating Salary Sacrifice in the Last Week of June
The most common EOFY super mistake: an Australian decides on 24 June to start salary sacrificing for the financial year, signs the form with their employer on 25 June, and the contribution does not clear their super fund until 7 July. The amount counts for the following financial year — and the current year's tax saving is gone.
The mechanics: salary sacrificed amounts must be received and processed by your super fund on or before 30 June 2026 to count toward the 2025–26 financial year. Most funds need 3–5 business days to clear electronic transfers. That makes the realistic cut-off around 23 June 2026, not 30 June.
The dollar value: Sarah (Melbourne, $112,000) wants to sacrifice $6,000 to use her remaining concessional cap room (her employer SGC at 12% is $13,440, leaving $16,560 of headroom under the $30k cap). At her 32% Stage 3 marginal rate plus 2% Medicare, sacrificing $6,000 saves her $1,020 in net tax for the year (32c per $1 saved on income tax minus 15c contributions tax = 17c per $1 net saving on $6,000). Wait one week too long and that $1,020 disappears for 2025–26.
Mistake 4 — Crossing the MLS Threshold Without Realising
The Medicare Levy Surcharge thresholds for 2025–26 are $101,000 for singles and $202,000 for families. Without complying private hospital cover for the full year, crossing those thresholds triggers a surcharge of 1.00% (Tier 1), 1.25% (Tier 2), or 1.50% (Tier 3) on your full MLS income — not just the amount above the threshold.
This becomes a 30 June problem when a mid-year pay rise quietly pushes someone over the line. A rise from $98,000 to $108,000 looks like a $10,000 win. After PAYG (32% Stage 3 plus 2% Medicare) the take-home gain is about $6,600. But the MLS at Tier 1 on $108,000 is $1,080 — paid on the full income, not just the extra ten grand. The "real" raise is closer to $5,520, not $6,600.
The dollar value: At Tier 1, MLS costs $1,010–$1,180/yr. At Tier 2 ($118,001–$158,000), it is $1,475–$1,975/yr. At Tier 3 (above $158,000), it is $2,370+. Basic hospital-only cover for a single typically costs $1,200–$1,800/yr — making hospital cover cheaper than the surcharge once you cross into Tier 2 territory. The break-even sits right around the Tier 1 / Tier 2 boundary at $118,000.
Mistake 5 — Underclaiming Work-from-Home in a Cost-of-Living Crisis Year
With headline CPI forecast to peak at 4.8% in the June quarter 2026, electricity prices up 9% in 12 months, and home internet up 6%, this is the year work-from-home deductions matter most — and the year most Australians under-claim.
The ATO's fixed-rate method for 2025–26 is 70 cents per hour worked from home. It covers electricity, gas, internet, mobile and home phone, stationery, and computer consumables. You cannot also claim those items separately under this method — but you can still separately depreciate the home-office furniture and computer equipment used. You need a contemporaneous diary or timesheet recording every hour worked from home — end-of-year estimates are not accepted under the post-2024 ATO compliance regime.
The dollar value: An Australian working from home 2 days a week (~16 hours/wk, ~768 hours/yr) claims $538 under the fixed-rate method. At Stage 3 plus Medicare (32% bracket): that is $172 in tax saved. Three days a week from home: $807 deduction, $258 saved. Most workers under-record by 30–50% because they only count "official" home days and miss evening / weekend admin time. A simple weekly diary entry — even retrospective for the last 11 months if you can substantiate — can recover hundreds in deductions.
The Bottom Line — What Sarah Should Do Before 23 June
Stitching the five mistakes together for Sarah (Melbourne, $112,000, total super under $500k, no carry-forward used, no hospital cover, 2 days WFH):
| Action | Cut-off date | Dollar impact |
|---|---|---|
| Use 2020–21 carry-forward super cap | 23 June 2026 | +$2,720 tax saved |
| Salary sacrifice $6,000 of FY25-26 cap room | 23 June 2026 | +$1,020 tax saved |
| Buy basic hospital cover (or accept Tier 1 MLS) | 30 June 2026 | $1,200 cover or $1,120 MLS — break-even |
| Claim 768 hours WFH at 70¢/hr | Tax return lodgement | +$172 tax saved |
| Fill up before 30 June; finalise logbook | 30 June 2026 | +~$30 fuel |
Combined: Sarah saves roughly $3,940 in 17 days of admin. That is the difference between the average EOFY result and a deliberate one. In a year when the RBA hike has cost her $3,360 in extra mortgage repayments and her grocery bill is 18% higher than two years ago, that $3,940 is the lever within her control.
Frequently Asked Questions
Q: I work from home 1 day a week — is it worth the diary admin?
At 8 hours per week (384 hours/year) at 70¢/hr, the fixed-rate deduction is $269 — about $86 saved at a 32% marginal rate. The diary is a 10-second entry per work-from-home day. Worth it.
Q: Can I lodge a personal deductible super contribution after 30 June but for 2025–26?
No. The fund must receive the money on or before 30 June 2026. The s290-170 notice of intent can be lodged later (before you file your tax return), but the contribution itself must clear the fund inside the financial year.
Q: My total super balance is $520k at 30 June 2025 — can I still use the 2020–21 cap?
No. The $500,000 total-super-balance threshold is a hard rule. If your total super balance was $500,000 or more on 30 June of the previous year, you cannot use any carry-forward room — the cap is "frozen" for that year. The 2020–21 amount still expires at 30 June 2026; it just cannot be used.
Q: I cancelled my hospital cover mid-2025 — am I exempt from MLS for the rest of the year?
Only for the days you held cover. The MLS is pro-rated daily. If you had hospital cover from 1 July 2025 to 31 December 2025 (184 days), you are exempt for that period; MLS applies for the remaining 181 days of the financial year on a pro-rated basis.
Q: I am self-employed — does Mistake 3 (salary sacrifice) apply to me?
The mechanics are different but the principle is identical. Self-employed Australians use personal deductible contributions (not salary sacrifice). The fund-clearance deadline is the same: by 30 June 2026, with the s290-170 notice lodged before tax return filing.