Your Bank Balance Is Not Your Money: The Tax Reserve Habit Sole Traders Build Early

The failure is rarely a spending problem. It is a visibility problem. In a job, PAYG withholding takes tax out before you see it, so your bank balance is genuinely yours. Go out on your own and that filter disappears. Every dollar a customer pays lands whole, and nothing in the banking app tells you which part of it was never yours. Someone posting on r/AusFinance described the moment it surfaced in a household: "She tells me yesterday that she owes 42,000 on her tax bill. I asked about her tax withholdings and she tells me she didn't do it. I asked where is the account with her tax income (previous years I know she's had an account that she 'doesn't touch' to pay her tax), and she tells me there's no money in it." Note the detail that matters. The account existed. The habit had been there in earlier years. What broke was the mechanism, not the intention. Once the reserve depends on someone remembering to move money after the money has already arrived and already been useful, it fails quietly and it fails for months before anyone notices. The second problem compounds it. If you are registered for GST and priced a job without adding GST, you did not just lose margin. You now owe the ATO out of money the customer never gave you, and an unlodged BAS hides that for a full quarter or longer.

Yes, and the framing is worth taking literally because it changes behaviour. GST is a tax on the end consumer. You are an unpaid collection agent for it. When a customer pays you an invoice with GST on it, roughly one eleventh of the total is money you are holding on the ATO's behalf, less the GST credits on what you bought. PAYG instalments are different in kind but similar in effect: they are prepayments toward your own income tax, calculated from what you earned last year, and they arrive whether or not this year is going as well. Businesses register for GST when turnover reaches the registration threshold of $75,000, or earlier by choice. Source: ato.gov.au. Once registered, your invoice price stops being one number and becomes two stacked together. Plenty of newly registered sole traders keep quoting the old price and absorb the GST silently. The consequences escalate for company directors. Unpaid PAYG withholding, GST and super can be pushed onto a director personally through a director penalty notice, and that applies even to someone whose name is on the paperwork without running the business. One post on r/AusLegal came from a man who had signed on as director of his father's business while his father went bankrupt, and who said he never took part in running it: "Long story short business got hard for him and he was getting cut short payments from clients and racked up a huge tax, super, payg and gst debt. I received a DPN notice and I’m looking at going into bankruptcy." Company structure does not quarantine these particular debts the way people assume it does.

There is no single correct number, and anyone giving you one without knowing your structure is guessing. What matters more is that the number is fixed, applied to every payment, and moved automatically. One sole trader's starting point, from an r/AusFinance thread on this exact question: "To stay on top of things, I’m putting aside 35% of every invoice paid into a separate savings account labelled “Tax - do not touch”." That is a reasonable default for a sole trader with meaningful income and few deductions, but it is one person's number, not a rule. Reserve for four things and size each separately. GST applies to every GST-inclusive payment received if you are registered, at one eleventh of the payment less GST credits on purchases. Income tax applies to net profit, not revenue, at your marginal rate on expected profit, checked with your accountant. PAYG instalments are quarterly once the ATO enters you into the system, and should be drawn from the reserve rather than from new revenue. Super is voluntary for sole traders and compulsory for employees. The safest approach is to over-reserve slightly and treat the surplus at year end as a genuine surplus, not as a windfall to spend. Under-reserving is the failure mode with teeth.

Willpower is the wrong tool because the decision happens at the worst possible moment: when money has just landed and something else is overdue. Remove the decision. First, open a separate account at a different institution to your operating account. Different login, different card, no card at all if possible. Name it so future-you cannot rationalise it. Second, set the sweep at the trigger point, not on a calendar. If your bank offers a rule that moves a percentage of every inbound payment, use it. Where the bank cannot do it, a small rule that watches for a payment-received event in Xero or MYOB and creates the transfer instruction works the same way. Third, reconcile monthly, not quarterly. A month of error is recoverable, a quarter of error usually is not. Fourth, lodge BAS on time even when you cannot pay in full. Lodging and paying are separate obligations, and lodging keeps the number visible instead of letting it accumulate in the dark. One warning: a money rule that somebody else built and nobody inside the business understands is worse than no rule. When it stops firing after a bank or invoice template changes, the reserve stops filling and the first sign is a bill. Whoever runs the money should be able to open the rule, read it and fix it.

The ATO calculates your quarterly PAYG instalment from your last lodged return. If last year was strong and this year is not, the instalment is sized for a business you no longer have. From r/AusFinance: "In other words, a single quarterly PAYG instalment is greater than any of my tax bills from the past 3 years. Wtf?" You can vary an instalment. The variation is made on the activity statement itself before the due date, and it applies to that instalment and the remaining ones in the year. Source: ato.gov.au, PAYG instalments. Vary too far down and general interest charge and penalties can apply on the shortfall, so the estimate has to be honest rather than convenient. Talk to your accountant before varying. The variation is easy to miss, and the posts on this topic tend to come from owners who did not know how the instalment was calculated in the first place. Without it, the options are paying an instalment sized for a better year, or ignoring the notice and letting it become debt.

There is a partial one, and it deserves a fair hearing. Cash in your own high-interest account earns you something. Cash sent early to the ATO earns you nothing. One reply in the r/AusFinance sole trader thread put it plainly: "Do not make early voluntary payments to the ATO, keep the money in your account earning interest until the ATO sends you a notice to pay." That is an argument about when to pay, not about whether to reserve. Reserving means the money sits in your own offset or savings account until the due date. It does not mean prepaying. The two get confused, and the confusion is used to justify leaving the money in the operating account where it gets spent. The other honest counter-argument: if the business cannot fund both operations and a reserve, the reserve is not the problem. The pricing is. Reserving reveals that faster than anything else.

Fifteen minutes, same day each month. Reconcile the bank feed so the numbers are real. Compare the reserve balance to the GST payable in your accounting software plus a rough income tax estimate on year-to-date profit. Adjust the sweep percentage if the reserve is drifting more than a little in either direction. Confirm the next BAS and instalment due dates are in the calendar. That is the whole habit. Nothing about it is sophisticated. It works because the decision has been removed from the day the money arrives.

**Is GST part of my income?** No. GST collected on your sales is money you hold on the ATO's behalf, offset by GST credits on your business purchases. It never belonged to the business. Treating GST-inclusive revenue as income is a common reason a profitable-looking year ends with a bill that cannot be paid. **What happens if I do not lodge my BAS?** Lodging and paying are separate obligations. Failing to lodge can attract failure-to-lodge penalties, and the ATO can issue a default assessment estimating what you owe, which itself carries a further penalty. Source: ato.gov.au, if you don't lodge. Lodging on time while paying late is far better than doing neither, because it keeps the liability visible and payment arrangements available. **Can I reduce my PAYG instalment if this year is worse than last?** Yes. You can vary the instalment on your activity statement before the due date, based on an honest estimate of this year's income. Varying too low can trigger general interest charge and penalties on the shortfall. Check the estimate with your accountant before you lodge the variation. **Does a company structure protect me from unpaid GST and PAYG?** Not reliably. Directors can be made personally liable for unpaid PAYG withholding, GST and super guarantee through a director penalty notice. The protection people assume a company gives them does not extend to these particular debts, especially where returns are unlodged. **How much should I reserve as a sole trader?** There is no universal figure. It depends on your profit, deductions, GST registration and other income. Pick a percentage with your accountant, apply it to every payment received, and correct it monthly rather than guessing once and hoping. Over-reserving slightly is safer than the alternative.

Reddit voice-of-customer quotes are reproduced verbatim and attributed to the subreddit only: r/AusFinance and r/AusLegal. External references: Australian Taxation Office, GST registration and the $75,000 turnover threshold, https://www.ato.gov.au/businesses-and-organisations/gst-excise-and-indirect-taxes/gst. Australian Taxation Office, PAYG instalments and varying an instalment, https://www.ato.gov.au/businesses-and-organisations/income-deductions-and-concessions/payg-instalments. Australian Taxation Office, if you don't lodge (failure-to-lodge penalties and default assessments), https://www.ato.gov.au/individuals-and-families/financial-difficulties-and-disasters/if-you-don-t-lodge. This article is general information, not tax advice. Confirm your own numbers with a registered tax agent.