How to catch up on overdue GST, VAT or BAS returns

Let 2Fin do the boring bits

Catching up is mostly sorting, and sorting is the part 2Fin takes off you. Bring in two years of bank statements at once — CSV, Excel or PDF, several files in one go — and Fin reads every line; in testing, 1,891 transactions came in in about a second on a desktop computer. Each transaction is categorised with its GST or VAT worked out, every overdue period is listed with its due date, and Fill all periods saves a draft of each one with a single press.

What is left for you is the decisions, not the data entry. Purchases are grouped by payee — the hardware store, the phone company, the software subscription — so you answer each payee once and the answer covers every period. Fin’s confident guesses (80% sure or more) can be accepted in one tap and undone one by one, and a payee can become a rule so the next import sorts itself. Every figure opens to the transactions inside it, and the finished statements export for you or your agent to check and lodge.

First, the reassuring part

Being a year or two behind is common, and every tax office has a route back. The penalties for filing late are usually fixed or capped; the bigger risks come from not filing at all — estimated assessments, larger penalties and, eventually, enforcement. Several offices also reduce penalties for people who come forward before they are contacted: the ATO treats an unprompted correction as a voluntary disclosure, Canada’s Voluntary Disclosures Program has given 75% interest relief and 100% penalty relief to unprompted applicants since 1 October 2025, and Inland Revenue takes 75–100% off a shortfall penalty disclosed before an audit notice.

So the goal is not perfection on day one. It is getting every overdue period filed with honest figures, in the right order, and talking to the tax office about anything you can’t pay.

Step 1: list every period you owe

Start from the date you registered (or should have registered) and your filing frequency. Two years of quarterly BAS or VAT returns is eight periods; New Zealand’s 2-monthly cycle makes it twelve; an annual GST/HST filer in Canada has two. The tax office’s online account shows which periods it expects, and that list is the one to match.

If you went over the registration threshold and never registered, that is a separate problem to raise first: in Australia, the UK, Canada and Singapore you can owe GST or VAT from the date you should have registered, even on sales where you never charged it. Registration can be backdated (generally up to 4 years in Australia), and telling the tax office before it finds out keeps the penalty lower. This is general information. Check what applies to you with a registered tax or BAS agent, or with the tax office.

Step 2: rebuild each period from your bank history

Your bank statements are the most complete record you have. Download two years of them as CSV, Excel or PDF from each account the business used, including any card you paid business costs on. Sales are the money in; purchases are the money out, less anything private.

Rebuilding by hand means sorting every line into a period and a GST or VAT treatment, then adding them up eight times. That sorting is the part software does well.

Step 3: check the purchases, and keep the invoices

Sales figures are usually straightforward. Purchases need judgement: what was business, what was private, what was a mix, and what was a large item such as a vehicle or equipment. Each tax office needs evidence for the credits you claim — in Australia a tax invoice for any purchase over $82.50 including GST — and credits have a time limit (4 years in Australia), so a catch-up is also the moment to claim the ones you missed before they expire.

Where a purchase was partly private, claim only the business part. Where you are unsure, leave the credit out and ask; you can usually claim a missed credit later, within the time limit, whereas an overclaim is a debt with interest.

Step 4: file everything, then deal with the money

File every overdue return, even the ones with nothing to report and even when you can’t pay. The ATO says to lodge so the amount owed is certain; Canada holds refunds until every required return is filed; Singapore and South Africa only consider a payment arrangement once the outstanding returns are in. In Australia, lodge the first statement of the financial year before the later ones.

Then pay what you can and ask for a plan for the rest: a payment plan with the ATO, Time to Pay with HMRC, a payment arrangement with the CRA, an instalment arrangement in myIR, or a deferral on SARS eFiling. Interest usually keeps running on a plan, so a shorter plan costs less. Finally, ask whether any penalty can be reduced or remitted — illness, disaster and similar reasons are considered by most offices.

Where 2Fin fits, country by country

2Fin prepares the statement from your categorised transactions and stops there: it never files or lodges anything. In Australia it prepares the BAS (G1 to G20, 1A and 1B, W1 and W2) for you to lodge through Online services for business or your BAS agent. In the United Kingdom it fills VAT Return boxes 1 to 9; it is not connected to Making Tax Digital, so you submit through MTD-compatible software or your agent. In Canada it prepares the GST34 with provincial HST rates, in New Zealand the GST101A and in Singapore the GST F5.

In India it fills GSTR-3B table 3.1(a) from your sales, and the input tax credit and other tables are yours to complete. In South Africa it fills the VAT201 summary fields. In the United States, sales tax is set by each state and 2Fin does not prepare it: your sales-tax tool or accountant files, working from the categorised income and spending 2Fin keeps. In every other country, GST or VAT is tracked on each transaction from the national rate on record, with a generic statement and accountant exports.

Importing your bank history and having it categorised starts free; preparing the BAS, VAT or GST statement is on the ELITE+ and AUTO+ plans (see plans).

How the time was measured

The times on this page come from one recorded run on 10 November 2026, not from a survey of users. The test case was a GST-registered sole trader with a salaried job on the side: two years of bank history, 1,891 transactions, and eight quarterly BAS not yet lodged. The file was imported into the 2Fin app and each quarter prepared from it, on a desktop computer.

The computer’s share — reading the file, categorising every row and filling all eight quarters — took under 3 minutes. The person’s share is modelled rather than stopwatched: 2.5 seconds for each tap and about 6 seconds to decide each payee. On that model the first quarter’s sales figures (G1 and 1A) take about 3 minutes and 18 actions, and all eight quarters, purchases included, take 7.5 to 11.5 minutes. A first-timer reading every screen will be slower; someone who knows their payees, faster.

Purchases are where the checking is. Fin grouped the 1,574 purchase rows into 30 payees, and one answer per payee (all business, part business, private, or a capital purchase) applied to every quarter at once. In that run the eight quarters’ GST credits (1B) came to $1,707.77 against the test’s answer key of $1,500.00, about 14% high; the gap matched the GST on two phone and internet payees answered as 50% business use, which the answer key left out. That is why the figures are prepared for your review, and why every BAS figure in 2Fin opens to show the transactions inside it.