28th December 2025

Tax Mistakes to Avoid in Australia

Ben Nash

Important: This is general information, not personal advice. Speak with a registered tax agent for your situation.

Why tax mistakes happen

The ATO gets smarter every year. Data feeds arrive from employers, banks, share registries, crypto exchanges and platforms. Lodge with missing income or inflated deductions and you can expect questions, amendments, and sometimes penalties. Most mistakes aren’t dodgy. They happen because rules are complex, people rush their return, or they copy last year’s numbers without checking what changed.

This guide covers the traps we see again and again. It explains wash sales, the latest work-from-home rules, rental property gotchas, crypto tax, car deductions, super contribution missteps, and when to wait for pre-fill. You’ll also find a practical ATO-safe checklist and answers to common questions. If you want to go deeper on the investment side, these pieces pair nicely with this guide: Tax-efficient investing in Australia, What is debt recycling, Should I invest or pay off my mortgage, and Restricted Stock Units in Australia.

The quick list: common mistakes the ATO flags

  • Lodging too early before pre-fill lands, then missing income
  • Claiming deductions without records that back them up
  • Treating improvements as repairs on rental properties
  • Claiming travel to a residential rental property
  • Misusing the work-from-home fixed-rate method
  • Double-counting car expenses or stretching kilometres
  • Treating crypto swaps as “no tax event”
  • Triggering a wash sale to chase a capital loss
  • Forgetting the notice of intent for personal super deductions
  • Ignoring Division 293 when income plus concessional contributions push past $250,000
  • Misclassifying share trader vs investor
  • Skipping voluntary disclosure when you spot an error

Below, we break these down and show how to stay on the right side of the ATO.

Wash sales: what they are, why they get people in trouble

A wash sale is when you sell an asset at a loss and then buy the same, or a substantially similar, asset again so your economic exposure hasn’t really changed. The aim is to book the tax loss without giving up the position. The ATO treats wash sales as tax avoidance and can deny the capital loss. That means your return gets amended, the loss disappears, and penalties can follow. The ATO has been explicit about this in its guidance. See Wash sales: The ATO is cleaning up dirty laundry.

Examples that raise a red flag

  • Selling 1,000 XYZ shares at a loss in late June, then buying back 1,000 XYZ shares a few days later
  • Swapping from ETF A that tracks the ASX 200 into ETF B that tracks the same index immediately, when your exposure is effectively unchanged
  • Crystallising losses in crypto on Friday and rebuying the same tokens on Monday to keep the same bag

What to consider instead

  • If you want to reduce exposure and harvest a loss, switch to a different exposure for a time, or wait a reasonable period before repurchasing
  • Document your investment thesis and trade history so your intent is clear and commercial, not tax-driven

Work-from-home deductions: the fixed-rate method most people get wrong

The ATO’s fixed-rate method lets you claim a set amount per work hour for additional running expenses. For 2024–25, the fixed rate is 70c per hour, and you still need to keep records of hours and certain expenses. Details here: ATO: Fixed rate method and the overview page Working from home expenses.

Common mistakes

  • No contemporaneous record of hours worked from home
  • Claiming separate items that are already covered by the fixed rate
  • Assuming a dedicated home office is required. The fixed-rate method doesn’t require a separate room, but records still matter

Make it ATO-safe

  • Keep a running log or digital timesheet
  • Save bills and purchase records for things you claim outside the fixed rate
  • If your pattern of work changes, update your records

Rental property traps: repairs vs improvements, travel, and loan redraws

Repairs vs improvements. Repairs fix wear and tear. Improvements add value or change the character of the asset. Repairs are generally deductible now, improvements are typically capital and claimed over time or added to cost base. See Repair and maintenance expenses.

Travel to residential rentals. Since 1 July 2017, individuals generally can’t claim travel expenses to inspect or maintain a residential rental property. The ATO’s page spells this out: Rental properties and travel expenses.

Interest apportionment and redraws. If you redraw on your investment loan for private spending, interest on that portion is not deductible. Track redraws carefully and apportion interest correctly.

Short-stay and private use periods. Airbnb weekends, family use, or vacant periods can change what you can claim. Keep a diary of nights available and nights actually rented.

Quick rental checklist

  • Keep invoices, leases, PM statements, and bank records in one folder
  • Separate repairs from improvements on quotes and invoices
  • Log any private use days, including your own stays
  • Record loan redraw purposes to support interest apportionment

Crypto tax: swaps can be taxable, and the ATO has the data

Crypto is often where people get into trouble with record-keeping and assumptions. Swapping one token for another can be a CGT event. Staking rewards are usually ordinary income. The ATO’s hub is here: Crypto asset investments and the transactions guide Crypto asset transactions.

The ATO also runs a crypto data-matching program covering 2014–15 to 2025–26. It pulls data from designated service providers to cross-check taxpayer reporting. Details: Crypto assets data-matching program protocol.

Crypto mistakes to avoid

  • Treating swaps as “no tax event”
  • Losing access to records and then guessing cost bases
  • Forgetting staking income
  • Ignoring overseas exchange accounts

Make it ATO-safe

  • Export transaction histories each quarter
  • Note your cost base in AUD at acquisition and disposal
  • Keep wallet addresses and TX IDs with your records

Car and travel deductions: stick to the actual method rules

For 2024–25, the cents-per-kilometre rate is 88c per km, up to 5,000 km per car, per year. You don’t need written evidence of each trip, but you do need a reasonable record of how you calculated your work kilometres. ATO details: D1 Work-related car expenses 2025.

Common mistakes

  • Estimating kilometres without any diary, log, or map history
  • Double-claiming fuel and cents-per-km
  • Claiming private trips as work trips

If your work travel is significant, consider the logbook method and keep it up to date. Pick one method and apply it correctly.

Super contribution potholes: notice of intent, caps, and Division 293

If you make personal super contributions and want a tax deduction, you generally must give your fund a valid notice of intent and receive an acknowledgment before lodging your return, or by the earlier of the return due date or end of the following income year. ATO form and instructions: Notice of intent to claim or vary a deduction for personal super contributions.

High-income earners can also be hit with Division 293 tax. If income plus concessional contributions are above $250,000, an extra 15% tax applies to some or all concessional contributions. ATO explainer: Division 293 tax.

Make it ATO-safe

  • Check contribution caps before you add money
  • Lodge your notice of intent on time and keep the acknowledgment
  • If you’re near $250,000, plan for potential Division 293

Shares: investor vs trader, and why it matters

The ATO distinguishes share investors from share traders. Investors usually hold on capital account. Gains are CGT and, after 12 months, may be eligible for the 50% CGT discount. Traders are running a business of trading. Gains are ordinary income, losses may be deductible on revenue account, and the CGT discount doesn’t apply to trading stock. The ATO’s guide is here: Share investing versus share trading.

Red flags

  • Thousands of transactions, short holding periods, and full-time trading behaviour
  • Business systems, capital at risk, and a profit-making intention that looks like a trading enterprise

If your activities change, the tax treatment can change too. Keep good records and be consistent with how you report.

Lodging too early: wait for pre-fill to reduce amendments

Every year the ATO reminds taxpayers to wait for pre-fill so bank interest, dividends, managed fund distributions, and employer income statements can land. Lodging in early July is a common way to miss income and trigger amendments. See ATO: Don’t lodge yet.

Practical moves

  • Check your myGov account for “tax ready” status
  • Confirm AMMA or AMIT statements for managed funds
  • Match share registry statements with CHESS statements and your portfolio tracker

Penalties if you get it wrong

The ATO can apply behaviour-based penalties for false or misleading statements:

  • 25% for failure to take reasonable care
  • 50% for recklessness
  • 75% for intentional disregard

Voluntary disclosure can reduce penalties if you correct errors before the ATO contacts you. See Penalties for making false or misleading statements.

Bottom line: keep tidy records, claim what you can prove, and fix mistakes quickly.

Your ATO-safe checklist

Records

  • Keep invoices, bank statements, share registry statements, and managed fund tax statements
  • Log work-from-home hours if you use the fixed-rate method
  • Save crypto transaction histories and TX IDs

Deductions

  • Repairs vs improvements: split invoices and claim correctly
  • Car deductions: use either cents-per-km or logbook, not both
  • Rental travel: don’t claim it for residential properties

Investments

  • Avoid wash sales. If in doubt, change the exposure or wait
  • Track cost bases, parcel IDs, and AMIT adjustments
  • Keep distribution reinvestment records for CGT

Super

  • Check caps, lodge the notice of intent, and keep the acknowledgment
  • If you’re near $250,000 income plus concessional contributions, plan for Division 293

Lodging

  • Wait for pre-fill and income statements to be tax ready
  • Cross-check registries and fund statements before you submit

FAQ

What is a wash sale in Australia?
A wash sale happens when you sell at a loss and buy back the same or substantially similar asset so your exposure hasn’t really changed, with the aim of generating a tax loss. The ATO treats it as tax avoidance and can deny the loss. Read Wash sales: The ATO is cleaning up dirty laundry.

What’s the current fixed rate for working from home and what records do I need?
For 2024–25, the fixed rate is 70c per hour. Keep a record of actual hours and evidence of eligible expenses you claim outside the fixed rate. See ATO: Fixed rate method and Working from home expenses.

Can I claim travel to my residential rental property?
Generally no since 1 July 2017. The ATO page is here: Rental properties and travel expenses.

Repairs vs improvements for rentals: what’s the rule of thumb?
Repairs fix wear and tear and are usually deductible now. Improvements are capital, typically claimed over time or added to cost base. See Repair and maintenance expenses.

Do I pay tax on crypto if I only swapped coins and didn’t cash out to AUD?
Often yes. Swapping one token for another can be a CGT event, and the ATO runs an ongoing crypto data-matching program. See Crypto asset investments and Crypto assets data-matching program protocol.

What’s the cents-per-kilometre rate this year?
For 2024–25, it’s 88c per km up to 5,000 km per car. See D1 Work-related car expenses 2025.

How do I claim a deduction for personal super contributions?
Lodge a notice of intent with your fund and get their acknowledgment before you claim. The ATO’s form and instructions: Notice of intent to claim or vary a deduction for personal super contributions.

What is Division 293 and why did I get a bill?
If your income plus concessional contributions exceed $250,000, an extra 15% tax can apply to some or all concessional contributions. See Division 293 tax.

Should I wait for pre-fill before lodging?
Yes, if you want to reduce amendments and letters from the ATO. Wait for your income statement to be marked tax ready and for investment pre-fill to arrive. See ATO: Don’t lodge yet.

Where strategy fits if you invest

Being right with the ATO is one side of the coin. The other side is setting up your investing so more return lands after tax and with less admin. If you want to dig into the practical levers:

If you want a second set of eyes on the investment side of your tax picture, a short chat can save a lot of back-and-forth at tax time.

Final word

The ATO doesn’t expect perfection. It expects reasonable care and good records. If you slow down, wait for pre-fill, and claim what you can prove, you’ll avoid most problems. Use the checklists, link to the ATO pages when you need the rule in black and white, and fix errors quickly if they pop up. That’s how you stay compliant and keep more of your money working for you.

 

If you want some help with your money, Ben has created a free seven-day challenge you can use to get more out of your money you can join here and permanently level up your money in just seven days. And if you want to learn how financial advice can help you, you can schedule a quick call here.

Disclaimer: The information contained in this article is general in nature and does not take into account your personal objectives, financial situation or needs. Therefore, you should consider whether the information is appropriate to your circumstances before acting on it, and where appropriate, seek professional advice from a finance professional.