Do I need to register for GST — and how does it work if I do?

What to watch for

Seven things, in the order the decision actually goes.

1. Answer the gate first — and if it's yes, the rest of the "should I" question isn't yours to ask. Section 51 puts the $60,000 as either a retrospective test (your taxable turnover in the past 12 months has exceeded $60,000) or a prospective test (you have reasonable grounds to believe it will exceed $60,000 in the next 12 months).¹ Either one triggers mandatory registration, and the prospective test is the one that catches people — you don't wait until you've actually crossed the line. The day a big contract or a clear growth trend makes $60,000 the reasonable expectation, the clock starts. Once you do trigger it, you have 21 days to register (that is three calendar weeks from the date you became liable — the statute says '21 days', which in NZ law means calendar days, not working days).² Miss it and IRD backdates your registration to when you should have registered, and you owe GST on every sale since out of money you've already spent and can't claw back from customers. The number to watch here is just your own turnover — and it doesn't reset on 31 March; it's a rolling 12 months at any point. If the gate is yes, stop weighing. You're in. Skip to #5 and #6 — filing frequency and accounting basis are the only choices left.

2. If the choice is genuinely yours, it turns on two things you already know. Below the threshold and expecting to stay there, you've probably already got a read on the two things that decide this — your likely customer mix, and roughly how buying-heavy you are versus time-heavy. That read is the call, near enough; it isn't a forecast you have to build. Who pays you: if your customers are GST-registered businesses, your GST is invisible to them — they claim it back as an input tax credit, so adding 15% costs them nothing and costs you nothing to charge. If your customers are consumers, the 15% is real to them: you either raise your price and look dearer than an unregistered competitor, or you keep the price and the GST comes out of your margin. What you buy: if you're an operation that spends heavily on GST-bearing inputs — stock, materials, gear, subcontractors — then not registering means you eat the 15% baked into all of it as dead cost. If you mostly sell your own time, there's little to claim back either way. Put together: business customers, or buying-heavy, or both → lean register. Consumer customers and few expenses → lean don't. (Under the hood it's a comparison — what you'd recover against what charging GST costs you — but you don't need to run that maths to read the two signals.)

3. Three situations where the answer is just "yes" — even well below $60,000. Some voluntary registrations don't need the weighing at all, because you're in a refund position from the start. Big setup spend coming: if you're about to drop real money on equipment, fit-out, vehicles, or opening stock, registering lets you claim the 15% back on all of it — common and sensible in an early-stage or capital-heavy business. You export, or your sales are zero-rated: exports are charged at 0%, but you still reclaim the GST on your local costs — so you're in a permanent net-refund position and IRD pays you regularly. (Zero-rated sales still count toward the $60,000 threshold even though you charge no GST on them — don't let "but I charge zero" talk you out of watching the line.) You expect to cross soon anyway: registering a little early avoids the mid-year scramble and the awkward moment of putting prices up 15% the week you tip over.

4. The genuinely hard part isn't the part you'd assume. The close calls — where what you'd recover and what charging GST costs you land near each other — turn on one input that's a real unknown: will your consumer customers wear a 15% rise, or will you end up absorbing it? No projection settles that cleanly, for you or for an accountant, because it's a judgment about your own market, not a number. So if the call is close, that's the moment to get a second opinion or run your actual figures through a tool that holds them — not because the maths is beyond you, but because part of the answer is a read on your customers that the maths can't make for you.

5. Once you're in: filing frequency is a cashflow choice, not a turnover one. Three options under sections 15 and 15B:³ monthly (mandatory over $24M turnover, optional for anyone), two-monthly (the default), six-monthly (optional under $500K turnover). For a small operator under $500K, six-monthly means fewer filing events but a bigger bill twice a year; two-monthly means more frequent, smaller reconciliations. The honest test is your own discipline: if the GST money sits in a separate account from the day it lands, six-monthly is fine; if "the GST money" is just whatever's left in the account on filing day, two-monthly forces you to face it more often and is structurally safer. Returns and payments are generally due the 28th of the month after the period ends — with two exceptions: the period ending 30 November is due 15 January, and the one ending 31 March is due 7 May.

6. Accounting basis is the bigger lever. Two main choices plus a hybrid. Invoice basis (section 19, the default): you account for GST when you invoice, paid or not.⁴ The trap is owing GST on money you haven't received — a $20,000 invoice your customer sits on for 90 days still puts $2,608 of GST on your next return. Payments basis (section 19A, available under $2M turnover): you account for GST when the money actually moves — cashflow-friendlier for service businesses with long-tail receivables, harder to reconcile against accrual accounting. Hybrid splits the two — invoice basis for your sales, payments basis for your purchases — and is unusual outside specific industries. For most sole operators, payments basis is the better default; you switch to invoice basis when you're forced (over $2M turnover, or — under section 19D — a single supply over $225,000 settled beyond 365 days) or when you've moved to proper accrual accounting.

7. Voluntary in is easy; getting out isn't free. There is no minimum registration period in NZ — you can apply to cancel as soon as your taxable turnover drops and is expected to stay below $60,000, or after 12 months of nil returns.⁵ The real cost of deregistering isn't a waiting period — it's the deemed supply: when you cancel, any business assets you keep are treated as supplied to yourself at market value, and you account for GST on that value in your final return. So register voluntarily for a reason that will hold — crossing the threshold soon, an input-heavy or B2B shape that pays back — not for a one-off year you'll want to reverse.

A separate point on what this decision actually is. Above the line it isn't a decision at all — it's an obligation, and the only real risk is missing the trigger and getting backdated, which is money straight out of your pocket. Below the line it is a genuine call, but one you're better equipped to make than the "run the numbers" advice implies, because the two things it turns on are things you know cold from your own trade. And where it does come out "register," the return isn't a one-off — every GST-bearing thing you buy, you claim the 15% back each cycle, which is real recurring cash for a buying-heavy or B2B operation. The accounting tool that asks you to tick "GST registered: yes / no" during setup isn't asking you a procedural question. It's asking you a strategic one — and now you know which two things the answer turns on.

Where this entry stops

This entry covers the registration decision and the inside-the-form choices. It doesn't cover:

• The mechanics of filing returns. The actual return-filing process on myIR (or via accounting software), how to claim input tax credits properly, how to handle adjustments and corrections — operational layer the wayfinder routes to IRD for. Worth doing the first one with an accountant if you're new to it.
• What goes on the invoice. Different question, separate entry. See first tax invoice.
• Zero-rated and exempt supplies in detail. Exports are zero-rated; residential rent and most financial services are exempt. The export net-refund case is named above, but if a meaningful chunk of your supplies sits in either category the calculation changes substantively — talk to an accountant rather than relying on a general entry.
• GST on imports. Customs collects GST at the border for goods over the de minimis threshold; the rules interact with your registration in specific ways. Specialist territory; route to IRD or a customs broker.
• Industry-specific GST treatment. Real estate, financial services, second-hand goods, gig-economy platform supplies — each layers specific rules on the standard framework. Talk to an accountant who knows your industry.

So: answer the gate first. If you're over $60,000 or reasonably expect to be, register — the only thing left to decide is how you file and how you account, and an accountant can set both in half an hour. If you're genuinely below and it's a close voluntary call, that's the one place the projection gets genuinely hard — get a second opinion or run your real numbers through a tool, because the deciding factor is a read on your own customers that no general entry can make for you.

Last verified 9 June 2026 against the Goods and Services Tax Act 1985 (sections 51, 8, 11, 14, 15, 15B, 16, 19, 19A, 19D, 52) at legislation.govt.nz and IRD operational guidance at ird.govt.nz. Full source list: references. The framework is stable; re-verification trigger is any amendment to the sections named above or any change to the threshold sub-thresholds.