The $75k GST threshold is rolling, not annual, and getting that wrong is expensive

Because almost everything else does reset on 1 July. Your tax return, your instalment cycle, your depreciation schedule. The GST turnover test is the odd one out, and nothing in the ordinary run of the year points that out. One seller described the trap on r/AusFinance: > I originally thought for some reason that the 75K threshold in which you need to register for GST was based off each financial year, which is why last financial year, I did something like 74.5K revenue (paused my store on purpose to not exceed it by the EOFY). I thought it reset back to 0, so I didn’t bother registering for GST….but now I realise that the 75K is on a rolling basis. The store was deliberately paused to land under the line. That is a real cost, paid in forgone revenue, for a rule that was misread. And it was not one person. Another commenter in the same thread on r/AusFinance replied: > Since when is it a rolling basis for 75k turnover? I thought it was annual unless something changed. Nothing had changed. The point is that two people in one thread held the same wrong model.

There are two limbs, and they work together. You must register once either one reaches $75,000, with one carve-out the ATO states plainly: even if your current GST turnover is at or above the threshold, you do not have to register if your projected GST turnover will be less than the threshold. Test | What it measures | When it bites. Current GST turnover | This month plus the previous 11 months | After the fact, when your trailing total crosses $75,000, unless your projected turnover for the next 12 months is below it. Projected GST turnover | This month plus the next 11 months | In advance, when you reasonably expect to cross. A few things that trip people up: GST turnover means gross business income, not profit. Your costs do not reduce it. It excludes GST itself, input-taxed sales, and sales not connected with Australia. You have 21 days from the point your turnover exceeds the threshold, not 21 days from the point you notice. Register late and the ATO can backdate registration to the date you were required to register. Backdating is the expensive part. You owe one eleventh of the GST-inclusive sales made in that period, whether or not you charged GST to those customers. You cannot invoice a customer from eight months ago for an extra ten percent. Backdating is capped at four years, unless there is fraud or evasion. The $75,000 rolling test is not the only path in. Drivers providing taxi, limousine or ride-sourcing travel for passengers must register regardless of turnover. So must anyone who wants to claim fuel tax credits. Non-profit organisations use a $150,000 threshold, and a new business that expects to reach the threshold in its first year of operation should register from the start. Source: ATO, Registering for GST, https://www.ato.gov.au/businesses-and-organisations/gst-excise-and-indirect-taxes/gst/registering-for-gst

Registration is a pricing event, and for consumer-facing services it is a nasty one. If you sell to other GST-registered businesses it is close to neutral. They claim the GST back, so your price can rise ten percent without changing their real cost, and you start claiming credits on your own inputs. If you sell to consumers there is no credit on the other side. You either raise your price by ten percent and ask households to wear it, or you hold your price and hand over one eleventh of every sale. On thin margins, that second option can be most of your take-home. A poster on r/ausbusiness put the squeeze plainly: > My concern - gah, who needs a price increase right now! If I register, I'll have to raise my prices, plus we're looking at absorbing merchant fees from Oct so that's what, an 11.4% increase on prices just to pay tax and fees. And no price rise for me personally. That is the real decision. Not "should I comply", but "which of these do I eat". The worst version is discovering it retrospectively, because then you have already eaten it without choosing.

For some businesses, honestly, yes. A consumer-facing sole trader with low input costs, genuinely happy at their current size, has little GST to claim back, so registration is close to a straight ten percent haircut. Pretending otherwise is not useful advice. But be honest about the cost. Capping turnover means refusing the job that would push you over, or pausing a store in June. It caps you permanently, because the reason never changes. And it only works if you are measuring, which is the part that usually fails. The counter-argument that matters: crossing with a plan is not a disaster. Six months of notice lets you stage a price adjustment, register at the start of a quarter, and claim credits on equipment you were buying anyway. The damage comes from the surprise, not the tax.

One number, checked monthly. Sum your last twelve months of sales, including the month just closed. Not financial year to date. Then set your own warning lines below the threshold rather than watching only $75,000. Worked through with example figures, that looks like this: Trailing 12-month turnover | What it means | What you do. Well below your watch line | Comfortable | Nothing, keep checking monthly. Watch line, say $60,000 | Watch zone | Model your GST-inclusive prices, talk to a BAS agent or accountant. Act line, say $68,000 | Act zone | Decide: register early and reprice, or actively manage capacity. Approaching $75,000 | Register | Within 21 days of exceeding the threshold. Where you set those lines depends on your own growth rate, so pick a gap that covers a few months of your typical sales. The point is to reach the threshold with enough lead time to change prices, tell clients, and update invoice templates before the obligation lands. The projected limb matters too. Sign a contract in March that you reasonably expect will take you past $75,000 over the next twelve months and you must register then, not when the money arrives.

Yes, and that is the sensible answer for anyone who has ever forgotten a monthly admin task. Your accounting software already holds the data. Xero, MYOB, and the trade platforms that feed them, ServiceM8, Tradify, Simpro, all know your invoiced sales by date. What you want on top of that is a rolling twelve-month total measured against a line you chose, and a message when it gets close. Check your own stack for that before you build anything. That is a small piece of work. Pull invoice totals for the trailing twelve months, sum them, compare against your two thresholds, email yourself on the first of each month with the number and the headroom left. Build it in-house rather than rent it, because the rule is yours. When the person who understands the business owns the check, it gets adjusted when the business changes. When an outside party owns it, it quietly stops matching reality and nobody notices until the number is wrong. The transferable skill is not connecting two apps. It is stating the rule precisely enough to encode it, and working out why the number is wrong when it disagrees with your accountant. That is diagnosis and process-mapping, and it applies to every other threshold you watch.

The confusion about the rule is matched by confusion about where to go. As one poster on r/AusFinance asked: > I also am not really sure who and where I am meant to find advice related to this. Do I find a BAS agent, a GST agent, an accountant or some tax advisor? A registered BAS agent can advise on and lodge GST and BAS matters, which covers registration timing and reporting. A registered tax agent or accountant covers that plus income tax and structuring, which is what you want if the real question is "stay under or grow through". "GST agent" is not a separate category. Check anyone you engage on the Tax Practitioners Board register at https://www.tpb.gov.au/public-register If you have already crossed without registering, see a registered agent before you contact the ATO. An agent can tell you your actual exposure rather than the worst case you are imagining.

**Is the $75,000 GST threshold per financial year or rolling?** It is rolling. The ATO tests turnover over the current month plus the previous eleven months, and separately over the current month plus the next eleven. It does not reset on 1 July. The one relief the ATO allows is that if your current turnover is at or above the threshold but your projected turnover for the next twelve months will be below it, you do not have to register. **What happens if I registered for GST late?** The ATO can backdate your registration to the date you were required to register. You then owe GST on sales made from that date, calculated as one eleventh of GST-inclusive amounts, even though you did not charge it. Backdating is limited to four years, unless there is fraud or evasion. You can claim credits on business purchases in the same period, which softens it. **Does GST turnover mean profit or revenue?** Revenue. GST turnover is gross business income from taxable and GST-free sales, excluding GST itself, input-taxed sales, and sales not connected with Australia. Expenses do not reduce it. A business with $80,000 of sales and $70,000 of costs is still over the threshold. **Should I register for GST voluntarily before I hit $75,000?** It depends who your customers are. If you sell mainly to GST-registered businesses, registering early is often net positive because they reclaim the GST and you claim credits on your inputs. If you sell to consumers, voluntary registration means a ten percent price rise or a ten percent margin cut with no offsetting benefit. **How much warning does a rolling twelve-month tracker give me?** That depends entirely on your growth rate, so set the alert far enough below $75,000 to cover a few months of your own typical sales. Whatever lead time you give yourself is time to model new prices, notify clients, time your registration to a quarter start, and bring forward equipment purchases so you can claim the GST credits. **Can I just stay under the threshold on purpose?** You can, and for some low-input consumer businesses it is rational. But it caps you permanently and only works if you measure a rolling total rather than a financial-year figure. Capping by accident, by pausing sales in June, costs revenue for a rule you have misread.

Quotes: r/AusFinance and r/ausbusiness. Reproduced verbatim, attributed to the subreddit only. Australian Taxation Office, Registering for GST: https://www.ato.gov.au/businesses-and-organisations/gst-excise-and-indirect-taxes/gst/registering-for-gst Tax Practitioners Board public register: https://www.tpb.gov.au/public-register Evidence note: the Reddit material here is a small number of Australian threads, not a survey. It shows the misunderstanding is real and recurring, not how common it is.