SERVICE · SINGAPORE
GST handled — from registration to every quarterly return.
Know exactly when you have to register, get registered properly, and never miss a GST F5 again. Our agents draft each return from your reconciled books; your accountant reviews the treatment and files with IRAS once you approve.
Facts checked on 12 September 2026
WHAT THIS COVERS
The work, in plain terms.
Goods and Services Tax is a tax that punishes small errors. Not because the rules are exotic — the standard rate is 9%, returns are quarterly, and the deadlines are fixed — but because GST touches every sale and every purchase, so a small error in how transactions are categorised becomes a systematic error across the whole return. By the time it shows up, it has been repeated for several quarters.
Synergy Accounting's GST service covers the full lifecycle: watching your taxable turnover so you register at the right time and not late, handling the registration itself, setting up your invoicing and accounting software so GST is captured correctly from day one, preparing and filing each GST F5 return, paying on time, and dealing with IRAS if they have questions. If you are already registered, we take over your next return and check the last few for anything that needs correcting.
The work is split deliberately. AI agents do the high-volume part — monitoring turnover, pulling transactions from your reconciled books, applying the right tax codes, drafting the return and tracking every date. A senior accountant does the part that needs judgement: reviewing the output and input tax treatment, deciding how unusual transactions are handled, and submitting the return only after you have seen it and approved it.
WHO IT'S FOR
Built for SMEs like these.
Businesses approaching S$1 million
You are growing and can see the compulsory registration threshold coming, or you are not sure whether you have already crossed it. You need someone watching the number and telling you what to do before IRAS tells you.
Newly registered and nervous
You have a GST registration number, your first return is due, and you are not confident your invoices, expenses and software are set up to get it right. You want the first return done properly so the pattern is correct from the start.
Registered, but returns are a scramble
Every quarter someone spends a weekend pulling numbers together, and there is a nagging feeling that input tax is being over- or under-claimed. You want returns that come out of the books automatically and a professional who has checked them.
THE SINGAPORE RULES
What the regulator expects.
These are the rules that decide whether you must register, when your returns are due, and what it costs to get them wrong. They are set by IRAS under the Goods and Services Tax Act and change from time to time — the current rate, for example, moved to 9% on 1 January 2024.
Registration is the decision that matters most. There are two tests, and either one can make registration compulsory: a retrospective test, looking back at the calendar year just ended, and a prospective test, looking forward twelve months. Businesses can fail the prospective test without realising it, because a large contract signed in one month can push the forecast over the line.
| Requirement | What applies |
|---|---|
| Standard rate | 9% on most goods and services supplied in Singapore, from 1 January 2024. Exports and international services are zero-rated; financial services, residential property sales and leases are exempt. |
| Compulsory registration — retrospective | Taxable turnover exceeded S$1 million in the calendar year just ended. Apply within 30 days of the year end; registration takes effect from the first day of the third month after that year. |
| Compulsory registration — prospective | You can reasonably expect taxable turnover to exceed S$1 million in the next 12 months. Apply within 30 days of forming that expectation; registration takes effect from the 31st day after the forecast date. |
| Voluntary registration | Available below the threshold if you make taxable supplies. You must stay registered for at least two years, complete IRAS's e-learning, and use GIRO for payments. |
| Filing frequency and form | GST F5, filed quarterly by default through myTax Portal. A nil return is still a return — it must be filed even if there were no transactions in the period. |
| Filing and payment deadline | One month after the end of each accounting period. For a quarter ending 31 March, the return and the payment are both due by 30 April. |
| Late filing | S$200 penalty as soon as the deadline passes, then S$200 for each further completed month, up to S$10,000 per return. IRAS may also issue an estimated assessment. |
| Late payment | 5% of the unpaid tax immediately, then an additional 2% for each completed month outstanding after 60 days, capped at 50% of the tax due. |
| Late registration | GST is backdated to the date you should have been registered — you owe it whether or not you charged customers — plus a penalty of up to 10% of that tax and a fine of up to S$10,000. |
| Record keeping | Tax invoices, receipts, import permits and the working papers behind each return must be kept for five years. |
Once registered you must issue tax invoices within 30 days of a supply, show your GST registration number on them, display GST-inclusive prices to consumers, and file GST F7 to correct errors in past returns. IRAS is also phasing in InvoiceNow for newly registered businesses — if it applies to you, we set it up during onboarding.
HOW WE HANDLE IT
Step by step, every period.
- 01
Threshold watch
From the day your books are with us, the GST agent tracks rolling taxable turnover against the S$1 million threshold on both the retrospective and prospective tests. When you get within reach, your accountant tells you what registering would mean for your pricing and cash flow — before the decision is forced.
- 02
Registration
We prepare and submit the GST F1 application, choose the right effective date and filing frequency, set up GIRO, and complete any e-learning IRAS requires. If voluntary registration makes sense for you — say, because your customers are mostly GST-registered and you have significant input tax — we say so.
- 03
Set-up in your software
Tax codes in Xero or QuickBooks Online, invoice templates with your registration number and the right wording, default treatments for your regular supplies and purchases, and rules for the awkward ones — overseas services, reimbursements, deposits. This is where future errors are prevented.
- 04
Quarterly draft
Because your bank is reconciled every month, the return is not a separate exercise. Two weeks before the deadline the GST agent assembles the F5 from the reconciled books, lists every transaction it was unsure about, and checks that input tax claims are backed by valid tax invoices.
- 05
Review and approval
Your accountant works through the draft and the exceptions list, decides how each flagged item is treated, and checks that the output tax reconciles to your sales. You then receive a short summary — total output tax, total input tax, the amount payable or refundable — and a request to approve.
- 06
Filing, payment and follow-up
Once you approve, the return is submitted on myTax Portal and the payment is scheduled so it clears by the deadline. If IRAS raises a query or selects you for an audit, your accountant handles the correspondence and pulls the working papers the agent kept for each return.
AGENTS + ACCOUNTANT
Who does what.
GST is a volume problem and a judgement problem at the same time. The volume — thousands of lines, each needing the right tax code, each input tax claim needing a valid invoice behind it — is exactly what agents are good at and people are bad at on a Friday afternoon. The judgement — is this a zero-rated export or a standard-rated local supply, is this reimbursement a disbursement, should this business register early — is where an experienced accountant earns their keep. Splitting the work this way means the return is both complete and correct, and there is one named professional accountable for it.
- Monitor your taxable turnover against the S$1 million threshold
- Draft the GST F5 from your reconciled books
- Track every filing and payment deadline
- Reviews output and input tax treatment
- Submits the return to IRAS once you approve
WHAT GOES WRONG WITHOUT IT
The expensive mistakes.
Registering late
The threshold is crossed in a strong year and nobody notices until the following year's accounts. IRAS backdates the registration, and the business owes 9% on a year of sales it did not charge GST on — money that cannot be recovered from customers — plus penalties.
Claiming input tax you are not entitled to
Motor cars, club subscriptions, staff medical costs and family benefits are 'blocked' input tax, and anything without a valid tax invoice cannot be claimed at all. Over-claims show up in IRAS reviews and attract penalties on top of repayment.
Treating every sale as standard-rated
Exports of goods and international services can be zero-rated if the conditions and documents are in place. Charging 9% where 0% applies makes you uncompetitive with overseas customers; zero-rating without the evidence gets the tax assessed on you later.
Missing a nil return
A quiet quarter with no sales still needs a GST F5. Businesses that assume 'nothing to declare' means 'nothing to file' collect S$200-a-month penalties on a return that would have taken minutes.
Returns built from bank statements rather than books
If the return is assembled from a bank export each quarter, deposits get treated as sales, transfers get counted twice and unpaid invoices are missed. Returns should come from reconciled accounts, which is why bookkeeping and GST are one workflow at Synergy Accounting, not two.
WHAT YOU RECEIVE
GST F5 filed on time, every quarter.
- A clear answer on whether and when you must register, updated as your turnover changes
- GST registration completed, with the right effective date and filing frequency
- Tax codes, invoice templates and treatments set up correctly in your accounting software
- A GST F5 draft every quarter, with an exceptions list showing what was checked
- A one-page approval summary before anything is filed
- Returns filed and payments scheduled on time, every quarter, with working papers kept for five years
- IRAS queries and audits handled by your accountant
Also on request: Personal income tax for directors, sole proprietors and partners is still handled on request — the same accountant who reviews your GST prepares the Form B or B1, so business and personal filings stay consistent.
INCLUDED IN YOUR PACKAGE
Included from the Growth package.
Your full finance function for a growing team. Every package is a fixed monthly fee with a named accountant on your file — see what each one includes and choose the right starting point.
Common questions.
Do I have to register for GST if my turnover is under S$1 million?
No. Registration is compulsory only when taxable turnover exceeds S$1 million on the retrospective or prospective test. Below that you can register voluntarily, which makes sense if most of your customers are GST-registered businesses and you pay a lot of GST on your own purchases — you can then claim it back. It makes less sense if your customers are consumers, because you would be adding 9% to your prices. We model both before you decide.
What counts as taxable turnover?
The value of standard-rated and zero-rated supplies you make in Singapore — broadly, your sales, including exports. It excludes exempt supplies such as financial services and residential property, the sale of capital assets, and supplies made outside Singapore. We calculate it from your books each month so you are not left guessing.
How often are GST returns filed?
Quarterly for most businesses, with each return due one month after the quarter ends. IRAS can approve monthly filing if you usually receive refunds, or half-yearly for some small businesses. We recommend the frequency that suits your cash flow when we register you.
What happens if we file or pay late?
A late return attracts S$200 immediately and S$200 for each further month, up to S$10,000. Late payment attracts 5% of the tax straight away and up to a further 2% a month after 60 days. Beyond the money, late filers are more likely to be selected for review. Our deadline tracking exists so this does not happen.
Can you take over if we are already registered and have filed returns ourselves?
Yes. We take over from your next return. As part of onboarding we review your recent returns and your software set-up; if we find errors, we tell you what they are and, where it is worth doing, file a GST F7 to correct them. Correcting voluntarily before IRAS finds an error significantly reduces any penalty.
Do you handle GST on imports and overseas services?
Yes. Import GST paid to Singapore Customs is claimable with the import permit as evidence. Services bought from overseas suppliers may fall under reverse charge if you are partially exempt, and overseas digital services are taxed under the overseas vendor registration regime. Your accountant sets the treatment for each of these when we configure your software.
Does an AI agent submit my return?
No. Agents draft the return and keep the working papers. Your accountant reviews it, you approve a summary, and the accountant submits it on myTax Portal. Nothing goes to IRAS without a person having checked it and you having said yes.
What do you need from us each quarter?
Very little if your bookkeeping is with us: the agents already have the reconciled transactions. You will occasionally be asked for a missing tax invoice or to confirm how an unusual transaction should be treated, by WhatsApp, and you approve the summary before filing.
Need this handled?
Tell us where the current process stands. We'll recommend a practical scope and clear next step.