Short answer: A good GST filing service in Singapore does more than key figures into the GST F5. It reconciles sales and purchases to the books, tests input tax claims, files through an authorised Corppass role before the one-month deadline, keeps a review trail, and, as InvoiceNow phases in, checks that the invoice data sent to IRAS matches the return.
If your company is GST-registered, it has to file a GST return every accounting period, usually every quarter, and the deadline does not move for staff turnover or a busy month. This guide explains what a GST filing service in Singapore should cover in 2026, how InvoiceNow changes the quarterly routine, what drives the fee, and which warning signs to look for when you choose someone to file for you.
Key facts at a glance
- GST filing and payment are due one month after the end of each accounting period. For the July to September 2026 quarter, that is 31 October 2026.
- A late return attracts an immediate S$200 penalty, plus S$200 for every completed month it stays outstanding, up to S$10,000 per return.
- If a return is not filed, IRAS may issue an estimated Notice of Assessment with a 5% late payment penalty. Repeated failure to file can lead to a court summons for the business and the persons running it, including directors.
- IRAS generally does not grant extensions. Staff resignations, year-end closing and lack of manpower are listed as reasons that will not be accepted.
- The GST InvoiceNow Requirement is being phased in from 1 November 2025 to 1 April 2031, with existing registrants grouped by their 2025 total annual supplies.
- Errors disclosed under IRAS’s Voluntary Disclosure Programme within the 1-year grace period from the filing deadline attract no penalty if the qualifying conditions are met.
- GST records must be kept for at least 5 years.
Raffles Corporate Services works with a panel of experienced Singapore law firms who offer cost-effective and efficient legal service and advice. This article is general information only and is not legal advice.
What should a GST filing service in Singapore cover each quarter?
At a minimum, a GST filing service should prepare the GST F5 return (the periodic GST return) from reconciled books, have it reviewed, and file it on myTax Portal before the due date. A better service also checks the riskier entries, flags errors for correction and keeps a file that would stand up in an IRAS review.
| Area | Basic filing | Fuller quarterly service |
|---|---|---|
| Return preparation | GST F5 figures taken from the accounting software | Figures reconciled to the general ledger, bank statements and sales records before filing |
| Output tax (GST charged on sales) | Standard-rated sales totalled | Standard-rated, zero-rated and exempt sales tested for correct treatment, including overseas customers |
| Input tax (GST claimed on purchases) | Claims taken as posted | Sample of invoices checked for valid tax invoices, business purpose and blocked items |
| Filing | Return submitted | Draft sent to the client for approval, submitted by an authorised Approver, acknowledgement saved |
| Errors | Not reviewed | Past-period errors identified and routed to the next-return concession or a GST F7 |
| InvoiceNow | Not covered | Invoice data transmitted to IRAS compared with the return figures |
| Records | None kept by the provider | Working papers and review notes kept for each quarter |
For the mechanics of each box on the return, see our guide on how to prepare and file GST returns accurately and on time and our walkthrough of how to file the GST F5 return correctly.
What steps should happen before the GST return is filed?
The work is in the checks before filing. A sound quarterly process usually runs in this order.
- Close the books for the quarter: all sales invoices issued, purchase bills entered and bank accounts reconciled.
- Review the GST codes on every transaction type, especially new customers, new suppliers and overseas transactions.
- Test input tax claims against the supporting documents. Our article on what you can and cannot claim as input tax covers the common exclusions.
- Check whether any supplier charging GST is actually GST-registered, using the GST Registered Business Search on the IRAS website.
- Reconcile the draft GST F5 to the general ledger GST control accounts.
- Where InvoiceNow applies, compare the invoice data sent to IRAS with the return.
- Send the draft return and a short summary of unusual items to the director or finance lead for approval.
- File through myTax Portal using a Corppass user with the Approver role, save the acknowledgement and arrange payment, or confirm the GIRO deduction.
IRAS publishes a free Pre-Filing Checklist as part of its Assisted Self-help Kit (ASK).
How does InvoiceNow change GST filing?
InvoiceNow is Singapore’s nationwide e-invoicing network based on the Peppol standard. Under the GST InvoiceNow Requirement, GST-registered businesses must also send invoice data to IRAS through an InvoiceNow-Ready Solution, so IRAS will see transaction-level data alongside the quarterly return.
IRAS’s phased timeline, as published on its GST InvoiceNow Requirement page, is:
| Implementation date | Who it applies to |
|---|---|
| 1 November 2025 | Companies that register for GST voluntarily within 6 months of incorporation |
| 1 April 2026 | Businesses applying for voluntary GST registration on or after 1 April 2026 |
| 1 April 2028 | New compulsory registrants from that date, and existing registrants with total annual supplies of S$200,000 or less |
| 1 April 2029 | Existing registrants with total annual supplies of S$1,000,000 or less |
| 1 April 2030 | Existing registrants with total annual supplies of S$4,000,000 or less |
| 1 April 2031 | Existing registrants with total annual supplies above S$4,000,000 |
Total annual supplies here means Box 4 of the GST return for the accounting periods ending in calendar year 2025.
Invoice data must reach IRAS by the earlier of the date the relevant GST return is filed and that return’s due date. In practice, invoices must be complete and correctly coded before the return goes in. For set-up steps, read our guide on getting an InvoiceNow Peppol ID and switching on GST submission.
InvoiceNow does not replace the return or shift responsibility. IRAS states that businesses remain responsible for filing accurate GST returns and keeping proper records for at least 5 years.
Who is responsible if a GST return is late or wrong?
The business is. Appointing a tax agent does not transfer the legal obligation, so the directors still need to know the return has gone in and is right. In practice, that means a director (or a finance lead the board trusts) should see the draft, ask about anything unusual and confirm the acknowledgement each quarter.
According to IRAS’s page on late filing or non-filing of GST returns, failing to file by the due date is an offence. IRAS may:
- issue an estimated Notice of Assessment with a 5% late payment penalty on the estimated tax;
- impose a late submission penalty of S$200 immediately, plus S$200 for every completed month, up to S$10,000 per return; and
- where a business repeatedly fails to file, issue a Notice to Attend Court or Summons to the business and the persons responsible for running it, including directors.
IRAS states that a business convicted in court may face a fine of up to S$5,000 for each offence, and that failing to attend court can lead to further action, potentially including a warrant of arrest against the director. The return still has to be filed.
Corppass matters too. A tax agent must be authorised in Corppass under the GST (Filing and Applications) e-Service. The Preparer role cannot submit; the Approver can.
Errors are a separate risk. IRAS allows a small error to be corrected in the next GST F5 if the net GST in error is not more than S$3,000 and the other boxes in error are not more than 5% of total supplies. Anything larger needs a GST F7. A good service tells you when this applies. Our article on correcting past GST errors and voluntary disclosure explains the options.
What drives the cost of a GST filing service?
The fee depends mainly on how much work sits behind the return, not on the form itself.
| Cost driver | Why it adds work |
|---|---|
| Transaction volume | More invoices and bank lines to code, reconcile and sample |
| State of the books | Unreconciled or late bookkeeping must be fixed before a reliable return can be prepared |
| Mix of supplies | Zero-rated exports, exempt supplies and overseas services need treatment checks and evidence |
| Foreign currency | Conversion and exchange rate checks on each foreign currency invoice |
| Imported services and reverse charge | Extra self-accounting entries and review |
| InvoiceNow status | Matching transmitted invoice data to the return each quarter |
| Corrections | GST F7 preparation or voluntary disclosure work for past periods |
| Special schemes | Schemes that require an ASK annual review at application or renewal |
Raffles Corporate Services publishes its fees on its packages page. As listed on 27 October 2026:
- GST filing as a standalone service: S$450 for existing clients and S$550 for non-existing clients.
- GST add-on for companies on an accounting package: from S$300 per quarter.
- Accounting packages billed quarterly: Starter at S$700 (up to 30 transactions a month, 1 bank account) and Standard at S$1,100 (up to 75 transactions a month, up to 3 bank accounts), with a 25% surcharge for multi-currency.
- GST registration: S$300 for existing clients and S$400 for non-existing clients.
Where volume or complexity goes beyond these packages, a custom quote is given after scoping. The free tools page is a useful starting point for gathering your figures before asking.
Should GST filing be bundled with bookkeeping?
For most small companies, yes. The return can only be as accurate as the books behind it, and a provider who keeps the books can fix coding at the source. A standalone service suits a company with a capable in-house bookkeeper and reconciled records. If you split the work, agree in writing who reconciles the GST control accounts and who handles InvoiceNow data. Our guide to GST record-keeping and staying ready for an IRAS audit sets out what to keep.
What are the warning signs when choosing a GST agent?
Watch for a provider who files without showing you the return or cannot explain the figures. Both usually mean no review is taking place.
- No draft is sent for approval before submission.
- The provider asks for your personal Singpass login instead of a Corppass authorisation.
- No reconciliation of the GST return to the general ledger is provided on request.
- Past errors are spotted but never corrected or disclosed.
- There is no plan for your InvoiceNow implementation date.
- The provider files close to the deadline every quarter, leaving no time to fix problems.
Do you need an ASK annual review as part of the service?
Usually not, unless you are applying for or renewing certain GST schemes. For those, IRAS makes the ASK annual review compulsory.
According to IRAS’s ASK page, the review is compulsory when applying for or renewing schemes such as the Import GST Deferment Scheme (IGDS) and the Major Exporter Scheme (MES). It must be performed, or certified, by an individual accredited with Singapore Chartered Tax Professionals as an Accredited Tax Advisor (GST) or Accredited Tax Practitioner (GST). For other businesses it is voluntary, but it helps find errors early enough to disclose them within the 1-year grace period.
Frequently asked questions
Can I get an extension to file my GST return?
Rarely. IRAS treats one month after the period end as a reasonable deadline. Extensions are considered only for listed reasons, such as a newly registered business filing its first return (up to 1 month) or an IT system breakdown (up to 2 weeks). The request must be made at least 5 working days before the due date.
Do I have to file if the company had no transactions in the quarter?
Yes. A GST-registered business with no activity in the period must still file a nil return. If the business has stopped trading, it should apply to cancel its GST registration.
When will my existing company have to use InvoiceNow?
It depends on total annual supplies for 2025. Existing registrants with S$200,000 or less start on 1 April 2028, with larger businesses following each April until 1 April 2031. IRAS has notified affected businesses of their dates and provides an implementation date calculator.
What happens if my GST agent makes a mistake?
The company is still responsible to IRAS for the correct tax. Small errors may be corrected in the next return under IRAS’s administrative concession; larger ones need a GST F7. Disclosing within the 1-year grace period under the Voluntary Disclosure Programme avoids penalties if the qualifying conditions are met.
For the corporate secretarial side, see our sister site Singapore Secretary Services.
Need help with this?
Raffles Corporate Services can handle the ACRA filings, compliance documentation and records for you, and where court proceedings or legal advice are needed, we work with a panel of experienced Singapore law firms who offer cost-effective and efficient legal service and advice.
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Last reviewed: 27 October 2026. The Editorial Team, Raffles Corporate Services.