If your business is GST-registered in Singapore, you are required to file a periodic GST return — called the GST F5 — with the Inland Revenue Authority of Singapore (IRAS). For most businesses, this is done quarterly. Filing incorrectly, late, or not at all exposes your business to penalties, late payment surcharges, and potential IRAS audits. This guide walks you through everything you need to know about the GST F5 return in 2026 — what it covers, how to complete it accurately, and what common mistakes to avoid.
What Is the GST F5 Return?
The GST F5 is the standard periodic GST return that most GST-registered businesses in Singapore file. It captures your total taxable supplies (sales), input tax claims (GST paid on purchases), and calculates whether you owe GST to IRAS or are entitled to a refund. The return is filed through the IRAS myTax Portal and must be submitted by the due date — typically one month after the end of each accounting period.
Other GST return types include the F7 (for correcting errors in past returns) and F8 (for businesses that are deregistering from GST). The vast majority of GST-registered businesses file F5 returns only. If you are not yet GST-registered but approaching the S$1 million annual turnover threshold, see our guide on GST Registration Singapore 2026.
GST F5 Filing Frequency and Deadlines
Most GST-registered businesses file quarterly. IRAS assigns each business a specific accounting period (e.g., January–March, April–June, July–September, October–December). The GST F5 return and any GST payable are due one month after the end of the accounting period.
| Accounting Period | Filing and Payment Deadline |
|---|---|
| 1 January – 31 March 2026 | 30 April 2026 |
| 1 April – 30 June 2026 | 31 July 2026 |
| 1 July – 30 September 2026 | 31 October 2026 |
| 1 October – 31 December 2026 | 31 January 2027 |
Businesses that miss two or more consecutive returns may be moved to monthly filing by IRAS — a punitive measure that dramatically increases the compliance burden. Some larger or higher-risk businesses are required to file monthly from the outset. Check the Singapore Company Compliance Calendar for all key tax deadlines throughout the year.
Understanding the GST F5 Return: Box by Box
The GST F5 form consists of 13 boxes divided into two main sections: supplies (sales) and purchases (expenses). Understanding what each box captures is essential to filing correctly.
Supplies Section (Boxes 1–4)
| Box | What to Enter |
|---|---|
| Box 1 – Total value of standard-rated supplies | Total sales subject to 9% GST (exclude GST amount). This includes most local sales of goods and services. |
| Box 2 – Total value of zero-rated supplies | Sales subject to 0% GST, e.g. exports of goods and international services. |
| Box 3 – Total value of exempt supplies | Supplies not subject to GST, e.g. financial services, sale or lease of residential properties. |
| Box 4 – Total value of goods imported under Major Exporter Scheme (MES) | Only relevant for MES importers — leave blank if not applicable. |
Purchases Section (Boxes 5–13)
| Box | What to Enter |
|---|---|
| Box 5 – Total value of taxable purchases | Total purchases on which input tax is being claimed. Enter the value excluding GST. |
| Box 6 – Output tax due | Calculated: Box 1 × 9% (GST rate). This is the GST you collected on your taxable sales. |
| Box 7 – Input tax and refunds claimed | Total GST paid on business purchases that you are claiming back from IRAS. |
| Box 8 – Net GST payable / refundable | Calculated: Box 6 minus Box 7. Positive = you owe GST to IRAS; Negative = IRAS owes you a refund. |
| Box 9 – Total value of goods imported under GST suspension | Relevant for specific import schemes. Leave blank if not applicable. |
How to File the GST F5 Return: Step by Step
- Log in to myTax Portal at mytax.iras.gov.sg using your company’s Corppass credentials. Ensure you have the “Preparer” or “Approver” role for GST filing.
- Navigate to GST → File GST Return (F5/F7/F8). Select the correct accounting period for the F5 return you are filing.
- Enter supply figures in Boxes 1–4 based on your sales records for the period. Use your accounting system’s GST report as the source.
- Enter purchase figures in Boxes 5–9. Only claim input tax on purchases that were incurred for business purposes and supported by valid tax invoices.
- Review the calculated output tax (Box 6), input tax (Box 7), and net GST (Box 8). Cross-check against your accounting records before proceeding.
- Save as draft if you need to have the return reviewed by an approver before submission.
- Submit the return by clicking “Submit”. An acknowledgement will be issued by IRAS.
- Pay any GST due by the filing deadline via GIRO, Internet Banking (IBG), or NETS. GIRO users receive an additional 15 days.
Input Tax: What You Can and Cannot Claim
Input tax is the GST you paid on business purchases. Not all GST paid is claimable — IRAS imposes restrictions on certain categories. You cannot claim input tax on:
- Medical expenses for employees (unless the business is a medical or healthcare provider)
- Club membership fees and subscriptions
- Family benefits (e.g., family trips, school fees)
- Expenses relating to private cars (S-plate or private-registered vehicles)
- Purchases used to make exempt supplies (e.g., residential property rental)
You can claim input tax on: office rent, utilities, professional services, employee business travel (for company-registered vehicles), equipment, computers, software, and most other business operating expenses — provided each claim is supported by a valid IRAS tax invoice from the supplier.
Common GST F5 Filing Mistakes
IRAS audits frequently uncover the following errors in GST F5 returns:
- Including GST amounts in the supply values: Boxes 1–5 should reflect the value of supplies and purchases excluding the GST component. A common error is entering the GST-inclusive amount, which results in overclaimed output tax.
- Claiming input tax without a valid tax invoice: IRAS requires a valid GST-registered supplier tax invoice to support every input tax claim. Receipts, quotes, and proforma invoices do not qualify.
- Missing the supplier’s GST registration number: Tax invoices must display the supplier’s GST registration number. Claims supported by invoices missing this detail may be disallowed on audit.
- Claiming input tax on disallowable expenses: See the list above. Medical expenses and club memberships are the most common slip-ups.
- Double-counting or missing transactions: Where a business uses multiple systems (e.g., separate invoicing and accounting software), reconciliation errors are common.
Penalties for Late or Incorrect Filing
Failing to file the GST F5 return on time results in a late filing penalty of S$200 per return, up to a maximum of S$10,000. Late payment of GST owed attracts a 5% late payment penalty plus interest. Providing false information on a GST return is an offence under the Goods and Services Tax Act (Cap. 117A) and can attract fines and in serious cases, imprisonment.
If you discover an error in a previously filed F5 return, you must file a GST F7 (Disclosure of Errors on GST Return) to correct it. Voluntary disclosure generally results in reduced penalties compared to errors discovered by IRAS during an audit.
GST Filing and Your Accounting System
Accurate GST F5 filing starts with an accounting system that properly categorises every transaction by GST code (SR for standard-rated, ZR for zero-rated, ES for exempt, OS for out-of-scope, TX for input-taxable purchases, etc.). Most modern cloud accounting systems — including Xero, QuickBooks, and MYOB — generate GST reports that map directly to the F5 boxes, dramatically reducing the risk of error and making the filing process straightforward. Integrating your accounting system with IRAS’s InvoiceNow e-invoicing network also helps ensure transaction data flows accurately. See IRAS’s guide to completing GST returns for further detail.
Conclusion
Filing the GST F5 return accurately and on time is a core compliance obligation for every GST-registered business in Singapore. The process is straightforward if your accounting records are well-maintained and your team understands which supplies and purchases fall into which GST categories. However, errors — even honest ones — can result in penalties or IRAS audits. If GST compliance is taking up more management time than it should, outsourcing your bookkeeping and GST filing to a professional firm is a practical and cost-effective solution.
Raffles Corporate Services provides GST filing, bookkeeping, and corporate tax compliance services for Singapore businesses of all sizes. Contact us today to find out how we can simplify your GST obligations.
— The Editorial Team, Raffles Corporate Services