ATO PAYG Warning: Why Australian Businesses Should Check Their Instalments Now (2026)

Quick answer: The ATO has flagged that many Australian businesses are paying incorrect PAYG (Pay As You Go) instalments — either too little, leaving them with a large end-of-year tax bill, or too much, locking up cash they could use in their business. Checking your instalment amount or rate now, before the financial year closes, can save you money and avoid penalties.

PAYG instalments are how the ATO collects income tax from businesses, investors, and self-employed individuals throughout the year, rather than in one painful lump sum at tax time. The system works well when your instalments are calibrated correctly — but when they drift out of alignment with your actual income, the consequences can sting in either direction.

The ATO's latest warning is a clear signal: don't assume your instalments are right just because the ATO calculated them. Businesses that have had a strong year may be underpaying. Businesses that have slowed down may be overpaying and unnecessarily tightening their cash flow. Here is everything you need to know to review your position before it becomes a problem.

What Are PAYG Instalments and Who Has to Pay Them?

PAYG instalments are periodic prepayments of your expected income tax liability. Instead of waiting until you lodge your tax return to pay everything you owe, the ATO collects tax progressively — usually quarterly — during the income year.

You enter the PAYG instalment system automatically when your tax liability and income cross certain thresholds. Broadly, you will be brought into the system if:

Your notional tax (based on your most recent tax return) is $500 or more, and
Your business and investment income exceeds $4,000 in a year

The ATO notifies you when you enter the system, and your first instalment notice arrives via your business activity statement (BAS) or instalment activity statement (IAS).

Who pays PAYG instalments?

Sole traders
Partnerships
Trusts
Companies
Investors with significant investment income (dividends, interest, rent)
Self-managed super funds (SMSFs)

Employees whose only income is salary or wages are generally not in the PAYG instalment system — their employer handles tax through PAYG withholding. But if you also earn investment income or run a side business, you may be pulled in regardless.

The ATO's Warning: What Has Gone Wrong?

The ATO's concern centres on two recurring problems.

1. Instalment Amounts Calculated on Outdated Income

The ATO sets your default instalment amount (or rate) based on your most recently assessed tax return — which, by the time you receive your BAS, could reflect income from 18 months ago or more. A lot can change in that time.

If your income has grown significantly since your last return, the ATO-calculated instalment will be too low. You will still technically meet your instalment obligations for the quarter, but at year end you could face a tax bill that is thousands of dollars larger than expected — plus potential interest charges if your shortfall is large enough.

If your income has fallen — due to a slow trading period, a major client lost, or broader economic pressures — your instalments may be set too high. You are essentially pre-paying tax on income you have not earned, which starves your working capital and provides the ATO with an interest-free loan.

2. Choosing the Wrong Method — and Not Revisiting It

The ATO offers two main ways to calculate your instalment:

Method	How It Works	Best For
Instalment amount (Option 1)	ATO sets a fixed dollar amount per quarter	Stable, predictable income
Instalment rate (Option 2)	You multiply your actual quarterly income by the ATO's rate	Variable or seasonal income

Many businesses lock in the instalment amount method at the start and never revisit it, even when their income pattern changes substantially. The instalment rate method requires more arithmetic but gives you a much tighter match between what you pay and what you actually earn each quarter.

How to Check Whether Your Instalments Are Right

Reviewing your PAYG instalment position does not require an accountant, though one can certainly help. Here is a practical approach.

Step 1 — Estimate Your Full-Year Taxable Income

Add up your income for the year to date and project forward to 30 June. Include:

Business revenue, less deductible expenses
Rental income, less allowable deductions
Interest and dividend income
Any capital gains you have realised or expect to realise

This is your estimated taxable income.

Step 2 — Estimate Your Tax Liability

Once you have an estimated taxable income figure, work out the approximate tax using the current individual (or company) tax brackets. For individuals in 2025–26, the brackets are:

Taxable Income	Rate
$0 – $18,200	0% (tax-free threshold)
$18,201 – $45,000	19%
$45,001 – $120,000	32.5%
$120,001 – $180,000	37%
$180,001+	45%

The Medicare Levy of 2% applies on top for most taxpayers.

For companies, the rate is 25% for base rate entities (businesses with aggregated turnover under $50 million, and with passive income not exceeding 80% of assessable income), or 30% for larger or passive-income-dominated entities.

You can use the Income Tax Calculator to quickly estimate your liability based on your projected annual income — it handles the Medicare Levy and offsets automatically.

Step 3 — Compare Against What You Have Already Paid

Check your activity statements for the year and add up the PAYG instalments you have paid. Compare this to your estimated tax liability.

If you have significantly underpaid: consider varying your next instalment upward, or setting money aside now so the end-of-year bill is not a surprise.
If you have significantly overpaid: you are entitled to vary your instalment downward and claim a refund of the overpayment through your tax return.

Varying Your PAYG Instalment: Your Rights and the Risks

One of the most useful — and underused — features of the PAYG instalment system is the ability to vary your instalment on any activity statement. You are not locked into the ATO-calculated figure.

When Should You Vary?

Income is materially higher or lower than the previous year
You have experienced a one-off event (asset sale, business restructure, large deduction)
Your business is seasonal and the quarterly instalment does not reflect the current quarter's performance
You have significant capital gains or losses that were not present in the prior year

How to Vary

In ATO Online Services (or through your accounting software), you can lodge a variation directly on your BAS or IAS. You nominate the new instalment amount you wish to pay for that quarter and state the reason.

The Risk: Getting It Wrong

Here is the catch. If you vary your instalment downward and your actual tax liability at year end turns out to be higher than what you paid in total instalments, the ATO may charge a general interest charge (GIC) — currently sitting above 11% per annum — on the shortfall.

Specifically, a penalty applies if your varied instalments for the year are less than 85% of your actual tax liability, and you varied them downward without a reasonable basis.

The lesson: vary with care and support your variation with genuine income projections, not wishful thinking.

Important: Keep a record of how you calculated your variation. If the ATO queries it, you want to show a logical, evidence-based estimate — not a number you chose to free up cash.

Common Mistakes Businesses Make with PAYG Instalments

Ignoring the BAS Entirely

Some small business owners, particularly sole traders who are new to the instalment system, simply pay whatever the ATO asks without questioning it. This is fine if your income is stable, but potentially costly if your circumstances have changed.

Conflating PAYG Withholding with PAYG Instalments

These are two different obligations that often appear on the same BAS, which causes confusion.

PAYG withholding is tax you collect from your employees' wages and remit to the ATO on their behalf.
PAYG instalments are prepayments of your own income tax.

Confusing the two can lead to paying the wrong amounts in the wrong boxes — a surprisingly common mistake, especially for new business owners.

Forgetting About Investment Income

Business owners who also have significant investment portfolios — shares, investment properties, term deposits — sometimes forget that this income also feeds into their instalment calculation. If you have had a strong year in the market or collected strong rental income, your total tax bill could be higher than your business income alone would suggest.

For property investors specifically, the Rental Income Tax Calculator can help you estimate how rental earnings affect your overall tax position.

Not Adjusting After a Business Sale or Windfall

Selling a business asset, receiving an insurance payout, or crystallising a large capital gain are all events that can dramatically change your tax bill for the year. Because the PAYG instalment system runs on autopilot, it will not automatically adjust for these events — you have to take action yourself.

Quarterly vs Annual PAYG Instalments

Not all businesses pay quarterly. Some smaller entities are allowed to pay a single annual instalment.

Lodgement Frequency	Who Qualifies
Quarterly	Most businesses and investors
Annual	Individuals with instalment income under $8,333/quarter (approximately $100,000/year) who choose not to use a BAS agent

If you qualify for annual instalments, the timing pressure is lower — but the risk of a miscalculation is higher, since you have less frequent checkpoints during the year.

What Happens If You Don't Pay?

Ignoring a PAYG instalment notice is a serious mistake. The ATO has a range of enforcement tools:

General Interest Charge (GIC): Applied on overdue amounts from the due date, currently compounding daily at a rate above 11% per annum.
Failure to Lodge Penalties: If you do not lodge your BAS, penalties can apply even if no tax is owing.
Director Penalty Notices (DPNs): For companies, the ATO can make directors personally liable for unpaid PAYG withholding (and, in some circumstances, GST) through a director penalty notice. This is separate from instalments but worth knowing.
Debt recovery action: The ATO can issue garnishee notices to your bank, intercept tax refunds, or pursue court action for large debts.

The ATO's firmer stance on business tax debt in 2025–26 means the days of quietly running up a tax debt without consequences are largely over. The agency has invested heavily in data-matching technology and is proactively contacting businesses whose payment patterns appear inconsistent with their reported income.

Practical Tips for Getting Instalments Right in 2026

1. Review your instalment amount at the start of every quarter. Before you submit your BAS, take five minutes to check whether your income for the quarter is in line with what the ATO has assumed. If it is materially different, vary.

2. Use accounting software that integrates with the ATO. Platforms like Xero, MYOB, and QuickBooks can pre-fill your activity statement and flag discrepancies. Some connect directly with ATO systems, which reduces manual errors.

3. Maintain a dedicated tax provision. Set aside a percentage of your income each month into a separate account earmarked for tax. A rough guide for sole traders: 28–33% of net business profit, adjusted for your marginal rate and any offsets you expect to claim.

4. Speak to your accountant before 30 June. With a few months of the income year still to run, there may be opportunities to time income or expenses in a way that reduces or smooths your tax liability — but only if you act before year end.

5. Check your Small Business Tax Offset eligibility. Sole traders who carry on a small business may be entitled to an offset of up to 16% of the tax attributable to business income, capped at $1,000 per year. This reduces your actual liability, which should flow through to your instalment calculation.

A Worked Example: How Getting It Wrong Costs You

Scenario: Maya, a freelance graphic designer

Maya earned $85,000 in net business profit in 2024–25. Her tax liability was approximately $19,717 (including Medicare Levy). The ATO set her 2025–26 quarterly instalments at $4,929 per quarter — totalling $19,717 for the year.

In 2025–26, Maya lands a major contract and her profit grows to $130,000. Her actual tax liability will be approximately $35,517.

But Maya does not vary her instalments. She pays $19,717 in total across four quarters.

At tax time, her shortfall is approximately $15,800. She has to find that money in July — and because her shortfall exceeds 15% of her actual liability, the ATO charges GIC on the unpaid amounts dating back through the year.

The fix: A mid-year income check in, say, January — when it was already clear she was tracking well ahead of the prior year — would have prompted Maya to vary her Q3 and Q4 instalments upward, spreading the payment more manageably and avoiding the interest charge entirely.

Frequently Asked Questions

What is the difference between PAYG withholding and PAYG instalments?

PAYG withholding is tax you deduct from your employees' wages and send to the ATO — it is someone else's tax that you are responsible for collecting. PAYG instalments are prepayments of your own income tax liability. Both may appear on the same BAS, but they are completely separate obligations.

Can I opt out of the PAYG instalment system?

Not if you meet the income and tax thresholds. The ATO automatically enrols you once your notional tax hits $500 and your business or investment income exceeds $4,000. However, you can exit the system voluntarily if your circumstances change — for example, if you cease business activity or your income drops well below the thresholds. Contact the ATO or speak to your registered tax agent.

What happens if I vary my instalment too low and underpay?

If your total instalments paid during the year are less than 85% of your actual tax liability, the ATO will charge a general interest charge (GIC) on the shortfall for each quarter you underpaid. The GIC rate compounds daily and is currently above 11% per annum, so the penalty adds up quickly.

Are PAYG instalments refundable?

Yes. When you lodge your tax return, the ATO credits all the instalments you paid during the year against your total liability. If you paid more in instalments than your actual tax bill, you receive a refund of the excess. This is one reason why overpaying instalments — while it avoids end-of-year surprise bills — is not ideal: you are giving the ATO an interest-free loan.

Does my company have to pay PAYG instalments separately from GST?

Yes. GST is a separate obligation that you collect on behalf of the government and remit via your BAS. PAYG instalments are your company's own income tax prepayment. Both appear on the same quarterly BAS for most businesses, but they flow into different accounts and have different rules. Underpaying one does not offset an overpayment in the other.

How do I change my instalment from the ATO's calculated amount?

Log in to ATO Online Services (via myGov for individuals, or through the business portal), navigate to your activity statement, and select the option to vary your instalment. Enter the new amount, nominate the reason code that best applies to your situation, and lodge. Your accountant or BAS agent can also do this on your behalf.

If my income fluctuates seasonally, is the instalment rate method better?

Generally, yes. The instalment rate method — where you multiply your actual quarterly income by the ATO-set rate — naturally scales up in good quarters and down in slow ones. This makes it a much better fit for seasonal businesses like retail, tourism, or agriculture. The trade-off is that you need to track your income carefully each quarter rather than just paying a fixed amount.

Related Calculators and Guides

Income Tax Calculator — Estimate your individual tax liability for the year to check whether your instalments are in the right ballpark.
Pay Calculator — Understand take-home pay and withholding for employees in your business.
Rental Income Tax Calculator — Factor in rental income when projecting your total taxable income.
Capital Gains Tax Calculator — If you have sold an asset this year, estimate the CGT impact on your year-end tax bill.
Superannuation Calculator — Concessional super contributions can reduce your taxable income and, by extension, your instalment obligations.

This article is current as at September 2026. ATO interest rates and instalment thresholds are reviewed regularly — always verify current figures before acting.

This article is for general information only and does not constitute financial, tax or legal advice. Individual circumstances vary. Consult a registered tax agent or licensed financial adviser before making decisions based on this information.