Is the $300 rule an automatic deduction?

No. The $300 rule is not a free or automatic deduction. You still need to have actually paid for a work-related expense and be able to explain the claim. It affects the level of written evidence required, not whether the expense needs to be real.

Can I claim fuel on top of the cents per kilometre rate?

No. The cents per kilometre rate already covers running costs such as fuel, servicing, registration, insurance and decline in value. Claiming fuel separately on top of the rate is double dipping. If you want to claim actual costs, you need to use the logbook method instead.

July 21, 2026

Common Tax Deduction Mistakes to Avoid in 2026

Q: Can I claim working-from-home expenses without records?

No. You need records to support working-from-home claims, including evidence of the hours you worked from home. For the fixed rate method (70 cents per hour for 2025-26), records such as timesheets, rosters, diary entries, calendar records or employer records are needed.

Q: Does the $1,000 standard deduction apply to my 2026 return?

No. The proposed $1,000 standard deduction for work-related expenses does not apply to the 2026 tax return. Your 2026 return covers the year ending 30 June 2026. Current deduction and record-keeping rules still apply.

Quick answer

The most common tax deduction mistakes in 2026 are claiming private expenses, guessing amounts, claiming without records, double dipping, claiming normal home-to-work travel, overclaiming phone and internet, getting working-from-home claims wrong, and treating ABN expenses like a free-for-all.

Most deduction mistakes come from one simple problem:

People start with what they want to claim, not what they can prove.

That is how tax returns go sideways.

The ATO’s deduction rules are not complicated at the headline level. You generally need to have paid the expense yourself, not been reimbursed, have a direct connection to earning income, and keep records.

Simple.

Not always followed.

GoTax helps Australians complete their tax returns online, with returns checked by registered tax agents before lodgement.

Start your 2026 tax return online with GoTax

The basic deduction rule

Before you claim anything, ask four questions:

Question	Why it matters
Did I pay for it?	You generally need to have incurred the expense
Was I reimbursed?	Reimbursed costs are usually not deductible
Was it connected to earning income?	Private expenses are not enough
Can I prove it?	Records support the claim

The ATO explains the basic rule in its guide on claiming deductions.

If your deduction fails one of those tests, pause.

If it fails all four, congratulations, you have found a tax problem wearing a receipt.

Mistake 1: Claiming private expenses

This is the classic.

People try to claim private expenses because the expense happened near work, during work, after work, because of work stress, or while thinking about work.

None of that is enough.

Common private expenses include:

normal clothing
home-to-work travel
personal phone use
private internet use
meals bought during a normal workday
gym memberships
childcare
family expenses
personal grooming
private subscriptions
household costs not connected to work

The tax law does not care that work made you tired, hungry or poorly dressed.

A private expense stays private unless there is a clear income-earning connection.

The ATO guidance on clothing, laundry and dry-cleaning expenses is a good example: normal clothing is generally not deductible just because you wear it to work.

That includes black pants.

That includes normal shoes.

That includes the shirt you call your “meeting shirt”.

Tax law has no respect for meeting shirts.

Mistake 2: Guessing deduction amounts

Guessing is not a deduction method.

It is a refund delay in training.

Common guessing mistakes include:

estimating phone use without a usage record
guessing work-from-home hours
claiming round numbers
using last year’s amount again
claiming 5,000 car kilometres without a basis
estimating tools and equipment without receipts
claiming “about half” because it feels reasonable

The ATO does not need every record to be dramatic.

But it does need the claim to be explainable.

Bad:

“I think it was around $900.”

Better:

“I claimed $912 based on these receipts and this work-use calculation.”

One is a guess.

The other has a spine.

Mistake 3: Claiming without records

A deduction is much stronger when it has evidence.

The ATO’s guide to records you need to keep explains the importance of keeping records for income and deduction claims.

Useful records may include:

receipts
invoices
bank statements
credit card statements
diary entries
calendar records
logbooks
odometer readings
payslips
email confirmations
app records
screenshots
written calculations

A bank statement can help.

But a bank statement may not prove what you bought or whether it was work-related.

“Officeworks $143” could be work supplies.

It could also be printer paper, a novelty mug and a laminator bought during an emotional stationery incident.

The ATO may want more detail.

Read the GoTax guide: What Records Does the ATO Actually Accept in 2026?

Mistake 4: Thinking the $300 rule is a free deduction

The $300 work-related expense threshold is commonly misunderstood.

It is not a free $300 deduction.

It does not mean everyone gets to claim $300 because they own shoes and once answered an email.

You still need to have actually spent the money.

You still need the expense to be work-related.

You still need to be able to explain the claim if asked.

If your total relevant work-related expense claim is over the threshold, written evidence requirements can become much stricter.

The safest way to think about it is this:

The $300 rule may affect the level of written evidence required.

It does not remove the need for the expense to be real.

Very inconvenient for people trying to claim imaginary stationery.

Mistake 5: Claiming the proposed $1,000 standard deduction in the 2026 return

There has been plenty of noise about the proposed $1,000 standard deduction for work-related expenses.

But it does not apply to your 2026 tax return.

Your 2026 return covers the income year ending 30 June 2026.

The proposed standard deduction is intended for the 2026–27 income year, generally lodged in 2027.

So for the 2026 return:

keep records
claim actual eligible deductions
do not assume $1,000 is automatic
do not throw away receipts
do not let a headline prepare your return

Headlines are good at getting attention.

They are less useful when the ATO asks for records.

Read the GoTax guides:

$1,000 Tax Deduction 2026 Return?

Don’t Throw These Tax Receipts Away Yet

Mistake 6: Claiming normal home-to-work travel

Ordinary travel from home to your regular workplace is usually private.

That rule annoys people every year.

It survives anyway.

The ATO’s guide to trips you can and can’t claim explains when travel may be deductible and when it is private.

Usually not deductible:

home to regular workplace
regular workplace to home
school drop-off on the way to work
personal errands during the day
weekend private driving
travel reimbursed by your employer

Potentially deductible:

travel between separate workplaces
travel from your workplace to a client site
travel between job sites
work-related travel during the day
ABN/business travel where properly recorded

The phrase “I need to get to work to earn income” is not enough.

That argument has been tried.

It did not become a national holiday.

Read: Car Expense Tax Deductions Explained for 2026

Mistake 7: Claiming 5,000 car kilometres automatically

The cents per kilometre method has a cap.

For the 2025–26 income year, the ATO’s cents per kilometre method uses 88 cents per eligible work kilometre, capped at 5,000 work-related kilometres per car.

The cap is not an invitation.

It is a limit.

You can only claim eligible work-related kilometres that you can reasonably support.

Bad:

“I claimed 5,000km because that is the maximum.”

Better:

“I calculated 4,280 eligible work kilometres from my calendar, diary and client visits.”

One is a claim.

The other is a guess wearing a fake moustache.

Read: Logbook vs Cents per Kilometre 2026

Mistake 8: Double dipping car expenses

If you use the cents per kilometre method, the rate already covers running costs such as fuel, servicing, registration, insurance and decline in value.

That means you do not claim fuel separately on top.

Double dipping mistakes include:

claiming cents per kilometre plus fuel
claiming cents per kilometre plus registration
claiming cents per kilometre plus insurance
claiming the same toll or parking cost twice
claiming costs reimbursed by an employer

If you want to claim actual costs, you need to look at the logbook method.

You do not get to build your own hybrid method because it feels generous.

That is not tax planning.

That is making soup out of rules.

Mistake 9: Getting working-from-home claims wrong

Working-from-home claims are a major error area.

The ATO’s working from home expenses guidance explains the methods and records required.

For the 2025–26 income year, the fixed rate method is 70 cents per hour.

Common mistakes include:

guessing hours
using round numbers
claiming every weekday without checking actual work pattern
claiming private home costs
double dipping costs covered by the fixed rate
claiming occupancy costs without meeting strict conditions
not keeping records of hours worked from home

A calendar can help.

A diary can help.

A roster can help.

“Worked from home most days, probably” does not help much.

That is not a record.

That is fog.

Read: What Is the 2026 Working From Home Fixed Rate?

Mistake 10: Overclaiming phone and internet

Phone and internet deductions are common.

So are phone and internet mistakes.

You may be able to claim the work-related portion of your phone or internet expenses if you use them for work.

But you need a reasonable basis.

Common mistakes include:

claiming 100% of a personal phone
claiming all home internet
not separating private use
no usage diary
no work-use calculation
double dipping with working-from-home fixed rate claims

Useful records may include:

phone bills
internet bills
call logs
data usage records
four-week usage diary
work-use calculation
employer communication records

If your phone is used for work, family, banking, sport, social media and avoiding calls from unknown numbers, then 100% work use may be a brave little fiction.

Read: Mobile Phone & Internet Tax Deductions

Mistake 11: Claiming normal clothing as a uniform

This is one of the oldest tax deduction mistakes.

Normal clothing is usually not deductible, even if:

your employer expects you to wear it
you only wear it to work
it looks professional
it is uncomfortable
it makes you feel underpaid

Potentially deductible clothing may include:

protective clothing
occupation-specific clothing
compulsory uniforms
distinctive uniforms

Usually not deductible:

ordinary black pants
regular shoes
business shirts
suits
dresses
standard work outfits
general fashion items

If normal clothing became deductible because it was worn to work, half the country would claim pants.

The tax system is not ready for that.

Possibly nobody is.

Mistake 12: Claiming donations that are not deductible gifts

Not every generous payment is tax deductible.

The ATO’s gifts and donations guidance explains that deductible gifts generally need to meet specific rules.

Common mistakes include claiming:

raffle tickets
fundraising chocolates
charity auction purchases
event tickets
GoFundMe payments that do not meet the rules
donations without evidence

A deductible donation is usually different from buying something at a fundraiser.

Even if the chocolate was for a good cause.

Even if the chocolate was emotionally important.

Tax law remains unsentimental.

Mistake 13: Treating ABN expenses like employee deductions

ABN holders, contractors, freelancers, rideshare drivers and sole traders often make a different type of mistake.

They either miss legitimate business expenses or claim private expenses as business costs.

Both are bad.

Common ABN mistakes include:

not declaring all ABN income
claiming private expenses
not separating business and private use
weak car records
poor home office calculations
claiming equipment without business-use percentages
mixing personal and business bank accounts
no invoice records
no business expense records

Having an ABN does not make everything deductible.

It just gives the ATO more categories to check.

Read the GoTax ABN Tax Deductions Guide.

Mistake 14: Missing income and only focusing on deductions

This is not technically a deduction mistake, but it damages tax returns all the time.

People obsess over deductions, then forget income.

Common missed income includes:

second jobs
bank interest
dividends
managed fund distributions
government payments
ABN income
rideshare income
delivery income
online platform income
rental income
short-stay accommodation income
foreign income
capital gains

The ATO receives information from many sources.

If you leave income out, a refund can turn into an adjustment later.

Not declaring income and then carefully claiming a $43 stationery deduction is like locking the front door while the roof is missing.

Focus on the whole return.

Not just the shiny deduction section.

Mistake 15: Copying last year’s return

Copying last year can be dangerous.

Your job may have changed.

Your work-from-home pattern may have changed.

Your car use may have changed.

Your income may have changed.

Your records may have changed.

The rules may have changed.

Common copied mistakes include:

same phone percentage
same working-from-home hours
same car kilometres
same donation amount
same laundry claim
same tools claim
same ABN expenses
same rental expenses

Last year is a useful reference.

It is not a template to blindly worship.

Tax returns are annual for a reason.

Mostly to irritate everyone, but also because facts change.

Mistake 16: Lodging too early

Lodging too early can create problems if income information is not ready.

Employer income, bank interest, private health insurance, dividends, managed funds and other information may not all be complete immediately after 30 June.

If you lodge before the information is complete, your return may be delayed, reviewed or amended later.

GoTax helps by stepping you through the return and checking it before lodgement.

The goal is not just fast.

The goal is fast enough and correct.

Fast and wrong is still wrong.

Just with more confidence.

Mistake 17: Relying on social media tax advice

Tax advice from social media is often confident, entertaining and wrong.

That is a dangerous combination.

Be careful with claims like:

“everyone can claim $300”
“claim 5,000km automatically”
“your phone is 100% deductible”
“gym gear is deductible because you need to stay fit for work”
“just claim it, the ATO won’t check”
“the $1,000 deduction applies now”
“your ABN means everything is a business expense”

The ATO does not accept TikTok logic.

Neither should you.

Use official guidance, proper records and registered tax agent review.

Less viral.

More useful.

What to do instead

Here is the clean deduction process.

List the expenses you paid.
Remove anything reimbursed.
Remove private expenses.
Check the income connection.
Work out any private-use percentage.
Keep records.
Use the correct method.
Check whether the claim belongs in 2026.
Do not double dip.
Lodge with proper review.

That is the whole game.

Not sexy.

Very effective.

If you want the broader deduction guide, read: What Tax Deductions Can You Claim in Australia in 2026?

You can also start from the Tax Deductions Australia hub.

How GoTax helps you avoid deduction mistakes

GoTax is built to make online tax returns easier and safer.

You work through the return online.
You enter your income and deductions.
You answer plain-English questions.
You include the records and calculations you have.
Your return is checked by registered tax agents before lodgement.

That helps reduce common mistakes like:

claiming private expenses
double dipping
missing obvious deductions
using the wrong car method
overclaiming phone and internet
getting working-from-home claims wrong
relying on weak records
forgetting ABN income or expenses

GoTax does not make silly claims safe.

It helps stop silly claims from getting lodged in the first place.

Which is much better than meeting the ATO later with a folder full of regrets.

Start your 2026 tax return online with GoTax

Quick mistake checklist before lodging

Before lodging your 2026 return, check:

Did I pay the expense myself?
Was I reimbursed?
Is the expense connected to earning income?
Is any part private?
Have I claimed only the work-related part?
Do I have records?
Did I use the correct car method?
Did I avoid double dipping?
Did I record working-from-home hours properly?
Did I calculate phone and internet use properly?
Did I exclude normal home-to-work travel?
Did I include all income?
Did I avoid copying last year blindly?
Did I check whether the rule actually applies to 2026?

If you can answer those properly, you are in better shape than most.

If not, fix it before lodging.

The ATO is easier to avoid than to explain yourself to.

Frequently asked questions

What are the most common tax deduction mistakes in 2026?

Common mistakes include claiming private expenses, guessing amounts, claiming without records, claiming normal home-to-work travel, overclaiming phone and internet, getting working-from-home claims wrong, double dipping car expenses and misunderstanding the $300 rule.

Is the $300 deduction automatic?

No. The $300 rule is not a free deduction. You still need to have actually spent the money and be able to explain the claim.

Can I claim 5,000 car kilometres automatically?

No. The 5,000km amount is a cap under the cents per kilometre method. You still need a reasonable basis for your eligible work-related kilometres.

Can I claim fuel as well as cents per kilometre?

No. The cents per kilometre rate already covers running costs such as fuel, servicing, registration, insurance and decline in value.

Can I claim normal clothes I wear to work?

Usually no. Normal clothing is generally private, even if you wear it to work. Protective clothing, occupation-specific clothing and compulsory uniforms may be different.

Can I claim my full phone bill?

Usually no, unless the phone is genuinely used only for work. Most people need to claim only the work-related percentage and keep records showing how they calculated it.

Can I claim working-from-home expenses without records?

You need records to support working-from-home claims, including records of hours worked from home and evidence of relevant expenses.

Does the $1,000 standard deduction apply to my 2026 return?

No. The proposed $1,000 standard deduction does not apply to your 2026 tax return. Current deduction and record-keeping rules still apply.

What happens if I make a deduction mistake?

The ATO may adjust your return, reduce your refund, ask for records, charge interest or impose penalties depending on the situation.

Does GoTax check deduction claims?

Yes. GoTax helps you complete your tax return online, and returns are checked by registered tax agents before lodgement.

Is home-to-work travel a deductible expense?

Usually no. Ordinary travel between your home and your regular workplace is generally private and not deductible, even if you need to get to work to earn income. Travel between separate workplaces, from a workplace to a client site, or work-related travel during the day may be deductible in some circumstances.

Can I claim donations to charities as a tax deduction?

You may be able to claim a donation of $2 or more to an eligible deductible gift recipient, provided you have a receipt and did not receive a material benefit in return. Raffle tickets, fundraising products, charity auction purchases and event tickets are generally not deductible.

Can ABN holders claim all their business expenses?

No. ABN holders can only claim expenses that are genuinely connected to earning their business or ABN income. Private expenses are not deductible. Business and private use must be separated, and records such as invoices, bank statements, logbooks and usage calculations are needed to support claims.

What should I do to avoid deduction mistakes before lodging?

Check that you paid each expense yourself and were not reimbursed, that each expense is connected to earning income, that private use has been removed, that records are available, that car kilometres are calculated correctly, that working-from-home hours are recorded and that you have not copied last year without checking whether your circumstances have changed. Having your return reviewed by a registered tax agent before lodging is the most effective safeguard.

About the Author

Written by Mark Walmsley, Chartered Accountant and Registered Tax Agent.