Setting Money Aside As You Earn It: A Habit That Saves Sole Traders at Tax Time

Most sole traders don't run into trouble because they're not earning enough. They run into trouble because the money that comes in during the good months gets spent before anyone has worked out how much of it was actually theirs to spend. By the time a BAS or a tax bill lands, a chunk of that money has already gone toward things that felt reasonable at the time: new equipment, a bit of a buffer for a slow week, a holiday that was overdue.

This is not really a budgeting problem. It is a sequencing problem. The habit that fixes it is simple to describe and genuinely useful once it becomes routine: set money aside as you earn it, not after you've already spent it and gone looking for it later.

Why income arrives looking bigger than it is

When a payment lands in a business bank account, it reads as one number. In reality, that number is doing several jobs at once. Some of it is GST you've collected on behalf of the ATO, if you're registered. Some of it is going to be owed as income tax once the financial year is totalled up. Some of it may need to cover superannuation contributions if you pay yourself that way. What's actually "yours" to spend on wages, materials, rent, or growth is whatever is left after those obligations are accounted for.

The trouble is that none of this is visible in a bank balance. A healthy-looking balance on a Tuesday afternoon doesn't distinguish between money that's genuinely available and money that's just sitting there until a quarterly or annual bill asks for it back. For a closer look at this distinction, it's worth reading about why profit and cash in the bank aren't the same thing — the two ideas are closely related.

The gap between "received" and "available"

A simple example makes the gap concrete. A sole trader issues an invoice for $2,200, GST-inclusive. Using the 1/11th rule, $200 of that is GST, which was never the trader's money to begin with — it was collected on behalf of the ATO and is owed back at BAS time. Of the remaining $2,000, some portion will eventually be taxed as income once deductions and the trader's overall tax position are worked out. What's left after that is what can genuinely be allocated to running the business or paying the owner.

None of this shows up automatically. The invoice total looks like $2,200 of income. Unless a system — mental, spreadsheet, or software — is actively separating out GST and putting aside a rough estimate for tax, that $2,200 behaves, in practice, like $2,200 of spendable cash. It isn't.

Why "I'll put money aside before BAS or tax time" rarely works

Plenty of sole traders know they should be setting money aside and plan to do it in a lump sum closer to when it's due. In practice, this approach tends to fail for a predictable reason: by the time the bill is close, the money has usually already been absorbed into ordinary spending. There's no single moment where it feels like "extra" money that's easy to set aside — it just becomes part of the operating balance, used for whatever the business needed that month.

Setting money aside after the fact also requires reconstructing, often under time pressure, how much should have been put away in the first place. That's a much harder calculation to do retrospectively and accurately than it is to do incrementally, transaction by transaction, as income actually arrives.

What the habit looks like in practice

The mechanics don't need to be complicated. The core idea is to treat GST and an estimated tax set-aside as money that was never fully "earned" by the business in the first place, and to move it out of the everyday operating account as soon as income is received, rather than waiting.

A separate account for money that isn't yours to spend yet

Many sole traders find it easier to open a second bank account — sometimes called a tax or GST savings account — and transfer a percentage of each payment into it as soon as it's received. The GST portion is straightforward to calculate: it's 1/11th of a GST-inclusive payment. The income tax portion is harder to pin down exactly, since it depends on the trader's overall income, deductions and personal circumstances across the year, but a conservative estimate set aside consistently is generally far better than nothing, and can be refined over time as a clearer picture of the year's income emerges.

Doing it per payment, not per month

The earlier in the cycle this happens, the more reliable it is. Setting aside money per payment, as it's received, means the habit doesn't depend on remembering to do a monthly review or having spare attention at the end of a busy month. It also means the operating account balance reflects something closer to the money that's actually available to spend, which makes day-to-day decisions — can I take on this expense, can I pay this bill now — more accurate.

Reviewing the estimate periodically

A flat percentage set aside for tax won't be exactly right, and that's fine. The purpose isn't precision, it's avoiding the situation where none of the money has been put aside at all. Reviewing the estimate every quarter or so, alongside BAS preparation, gives a natural checkpoint to adjust the percentage if income or expenses have shifted meaningfully.

Why this habit pays off beyond tax time

The value of setting money aside as income arrives isn't limited to avoiding a shock at BAS or tax time, although that's the most obvious benefit. It also changes the quality of day-to-day decisions, because the numbers in the main operating account start to reflect reality more closely.

Clearer pricing and spending decisions

A business owner who knows that their visible bank balance is close to their actual available funds can make faster, more confident decisions about things like taking on a new expense, hiring help for a busy period, or quoting a job. A business owner working from an inflated balance — one that includes GST and future tax obligations — is, often without realising it, making those decisions on figures that don't hold up once the bills come due. This is part of the same underlying issue explored in pricing jobs without knowing your real costs: decisions made on incomplete numbers tend to look fine in the moment and cause trouble later.

Less stress around BAS and tax time

When GST and an estimated tax set-aside have already been separated out as income arrives, BAS and tax time become largely administrative — checking figures, lodging, paying what's been set aside. They stop being a scramble to find money that's already been spent. This is one of the more direct ways day-to-day bookkeeping habits reduce stress at the pointy end of the quarter or the financial year.

A habit, not a one-off fix

There's no single tool or account structure that makes this automatic — it relies on a consistent habit, applied to each payment rather than caught up on later. For sole traders using software to track income and expenses, it's worth checking whether GST on each transaction can be automatically split out and viewed separately from the running total, since that visibility is what makes the "set aside as you go" habit easier to sustain. Because individual circumstances around tax obligations, super and GST registration vary, it's generally worth discussing the right set-aside percentage for a given situation with a registered tax agent or BAS agent, and referring to ato.gov.au for current guidance on GST and income tax obligations.