If your business should have registered for GST but did not, IRAS will backdate your registration to the date you ought to have been registered, and you must account for and pay GST on all sales from that date, even though you never charged it. Late notification can also attract a fine of up to S$10,000 and a penalty of 10% of the GST due. If you apply and voluntarily disclose that you are late, IRAS says it will generally waive the fine and penalties, and it may let you pay the backdated GST in instalments. The GST itself is not waived.
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.
When should you have registered?
Registration is compulsory if your taxable turnover passes S$1 million under either of two tests set out on IRAS’s GST registration page:
| Test | When it is met | Deadline to apply | Date you are registered |
|---|---|---|---|
| Retrospective | Taxable turnover for a calendar year (1 January to 31 December) exceeded S$1 million | 1 to 30 January of the following year | 1 March of the following year |
| Prospective | At any time, you can reasonably expect taxable turnover in the next 12 months to exceed S$1 million, for example after signing a large contract | Within 30 days of the date of the forecast | 2 months from the forecast date, for liability arising on or after 1 July 2025 (previously the 31st day) |
There is a limited exception if you exceeded S$1 million in a calendar year but can show that turnover in the next 12 months will not exceed S$1 million. You must keep evidence to support that.
Taxable turnover is not the same as all your income, and how it is added up depends on your structure. A sole proprietor combines all sole proprietorships and personal trade income. Partnerships with the same partners are combined. Each company is assessed on its own. Where a business has been split across entities to stay under the threshold, IRAS may combine them anyway: see our guide on related businesses and GST registration.
What does late registration cost?
- Backdated registration. Your effective date of registration is the date you should have been registered.
- GST on past sales. You must account for GST on sales from that date, whether or not you charged it. The rate is the one in force at the time of each sale: 7% before 2023, 8% in 2023 and 9% from 1 January 2024.
- Fine and penalty. A fine of up to S$10,000 and a penalty equal to 10% of the GST due for late notification, with prosecution possible.
- Possible wider review. Where turnover was under-declared or deliberately spread to stay below the threshold, IRAS may also look at income tax and treat the matter as evasion.
The GST on past sales is usually the largest cost. On S$1.5 million of sales in a year at 9%, it is a substantial sum that was never collected from customers.
How to register late and limit the damage
- Work out the correct registration date. Rebuild monthly turnover from bank statements and sales records and apply both tests. Many businesses discover that the prospective test was triggered earlier than they thought, for example by a large contract.
- Calculate the backdated GST. List the sales in each period from the registration date and the GST due on them, and identify purchases on which input tax may be claimable once registered, subject to the usual conditions.
- Apply and disclose. Submit the GST registration application on myTax Portal and state clearly that you are applying late and disclosing it voluntarily. IRAS says it will generally waive the late notification fine and penalties in that case.
- Ask about instalments. If the backdated GST cannot be paid in one sum, IRAS may allow instalments. Keep to any plan agreed.
- Talk to your customers. You may recover the GST from customers who agree to pay it, either by issuing credit notes and new tax invoices, or one tax invoice for the GST amount that references the original invoices. GST-registered customers can generally claim it back.
- Set up for the future. Start charging GST, file returns on time and keep the records IRAS expects of a GST-registered business.
Acting before IRAS contacts you matters. If you have already received an IRAS letter, such as a Voluntary Disclosure Opportunity letter asking you to check your liability to register, the deadline in that letter is the window for coming forward.
Example
Example only, not a client case. A renovation company’s sales were S$820,000 in 2024. In March 2025 it signed two contracts worth S$700,000 to be billed within the year, and in the full year 2025 its sales were S$1.4 million. It did not register. The prospective test was likely met in March 2025, when the contracts made turnover of more than S$1 million in the next 12 months a reasonable expectation. Because that liability arose before 1 July 2025, registration would have been effective on the 31st day after the forecast. GST is due on sales from that date. The retrospective test, applied in January 2026, would also have required registration, but the earlier prospective date is the relevant one.
Frequently asked questions
Can IRAS waive the backdated GST?
No. IRAS states that GST is a self-assessed tax and that backdating and payment of the backdated tax cannot be waived. Only the late notification fine and penalties are generally waived on voluntary disclosure.
Can I register voluntarily from today instead?
Not if you were already liable. Voluntary registration is for businesses below the threshold, and it is not backdated. A business that was liable must be registered from the date of liability.
We are a new company. Does the turnover of the old business count?
If you acquired a business, its taxable turnover is included in deciding whether you must register. A change of business structure, such as converting a sole proprietorship into a company, needs a fresh GST registration where the new entity is liable.
See our GST registration and filing services, our guide to correcting past GST errors, and the tax and GST hub.
Should your business have registered for GST already?
If your company, or you as a director or shareholder, suspects the business passed S$1 million without registering, contact the Raffles Corporate Services team at [email protected] or on WhatsApp at +65 8501 7133 or +65 9018 0072. We will work out the correct registration date and the GST due, prepare the late registration and voluntary disclosure, and handle the correspondence with IRAS, including any instalment request. Raffles Corporate Services is a corporate services provider, not a law firm, and this article is general information, not tax advice for your situation.
Kevin Yeo, Raffles Corporate Services