A business must register for GST if its taxable turnover was more than S$1 million in the past calendar year, or if it can reasonably expect taxable turnover to exceed S$1 million in the next 12 months.
The first is the retrospective test. The second is the prospective test. Businesses below the threshold may also apply for voluntary registration if they qualify and are prepared to meet the ongoing conditions.
Singapore’s current GST rate is 9%. A business must not charge GST until the effective date stated in IRAS’s approval letter.
GST registration is based on taxable turnover, not profit. A business can therefore be required to register even if its profit margin is low or it made an accounting loss.
The key is to monitor turnover throughout the year and apply as soon as either compulsory registration test is met.
When must a business register for GST?
| Registration basis | When it applies | When to apply |
|---|---|---|
| Retrospective | Taxable turnover was more than S$1 million for the calendar year from 1 January to 31 December. | Between 1 and 30 January of the following year. |
| Prospective | The business can reasonably expect taxable turnover to be more than S$1 million in the next 12 months. | Within 30 days after the date of the forecast. |
| Voluntary | The business is not required to register but qualifies and chooses to do so. | At any time after considering the conditions, costs and benefits. |
IRAS provides a GST Registration Calculator to help businesses check their position.
This guide covers the usual registration rules for a local business making supplies in Singapore. Separate rules may apply under reverse charge or the overseas vendor registration regime.
What counts as taxable turnover?
Taxable turnover is the total value of taxable supplies made in Singapore in the course of business.
It generally includes:
- Standard-rated supplies, which are usually subject to GST at 9%
- Zero-rated supplies, such as qualifying exports and international services
It generally excludes:
- Exempt supplies
- Out-of-scope supplies
- The sale of capital assets
Turnover is not the same as profit. It is measured before deducting business expenses.
IRAS explains the current calculation in its GST registration liability guide.
How does the retrospective test work?
At the end of each calendar year, add up the business’s taxable turnover from 1 January to 31 December.
If the total was more than S$1 million, the business must apply for GST registration between 1 and 30 January of the following year. Its effective registration date will generally be 1 March.
Example
A business records taxable turnover of S$1.08 million from 1 January to 31 December 2026.
- Application period: 1 to 30 January 2027
- Effective GST registration date: 1 March 2027
The business starts charging GST only from 1 March 2027, unless IRAS states another effective date.
Crossing S$1 million partway through the year does not always trigger immediate registration under the retrospective test. If the prospective test does not apply, assess the full calendar-year turnover at year end.
How does the prospective test work?
The prospective test applies when there is a reasonable and supportable expectation that taxable turnover will exceed S$1 million in the next 12 months.
Evidence may include:
- A signed contract or agreement
- An accepted quotation
- A confirmed purchase order
- Fixed recurring invoices
- An established sales trend showing that turnover is likely to exceed the threshold
A business plan, sales target or optimistic forecast alone is generally not enough.
The business must apply within 30 days after the date of the supported forecast. For liabilities arising on or after 1 July 2025, the effective GST registration date is generally 2 months from that forecast date.
Example
A customer accepts a quotation worth more than S$1 million on 2 September 2026, and the amount will be invoiced over the following 12 months.
- Application deadline: 2 October 2026
- Effective GST registration date: 2 November 2026
The 30-day application deadline and the 2-month period before GST charging begins are separate. Do not delay the application until the effective registration date.
Can a business avoid compulsory registration?
There are limited situations where a business may not need to register even after crossing the retrospective threshold.
For example, the business may qualify for an exception if:
- It is certain that taxable turnover for the next 12 months will not exceed S$1 million;
- The decline is due to specific circumstances, such as the end of a major contract or a substantial downsizing;
- It keeps documents supporting the forecast; and
- It is not liable to register under reverse charge.
A business making wholly or mainly zero-rated supplies may also apply for an exemption from registration.
These are specific exceptions, not automatic waivers. Keep the supporting documents and check the position against IRAS’s current rules before relying on them.
Should a business register voluntarily?
A business below the compulsory threshold may apply voluntarily if it makes, or has firm plans to make, qualifying supplies.
Voluntary registration can be useful where:
- Most customers are GST-registered and can claim the GST charged
- The business pays significant GST on purchases or imports
- The business mainly makes zero-rated supplies and may claim input tax
- Turnover is already close to the compulsory threshold
It may be less attractive where most customers are consumers or non-GST-registered businesses. If the selling price cannot be increased, the business may need to absorb the GST and reduce its margin.
Conditions for voluntary registration
A voluntary registrant must generally:
- Use GIRO for GST payments and refunds
- Remain GST-registered for at least 2 years
- Comply with all GST invoicing, accounting and filing duties
- Make taxable supplies within 2 years if it has not started doing so
- Complete the required GST e-learning unless an exemption applies
- Comply with the GST InvoiceNow requirement where applicable
IRAS recommends assessing the costs and benefits over the full 2-year minimum period. Its voluntary registration guide explains the factors in more detail.
How do you apply for GST registration?
GST registration is submitted online through myTax Portal.
- Confirm the registration basis. Decide whether the application is compulsory under the retrospective or prospective test, or voluntary.
- Prepare the figures and supporting documents. This may include turnover records, contracts, accepted quotations, purchase orders, invoices and business plans supported by actual activity.
- Complete the GST e-learning if required. This generally applies to voluntary applications unless the relevant exemption conditions are met.
- Check Corppass access. The person filing must be authorised for IRAS GST digital services. Our guide on what Corppass is and how it is used provides more background.
- Submit the application. Log in to myTax Portal and select GST, followed by Register for GST.
- Complete the GIRO setup. Voluntary applicants must submit a GIRO application.
- Respond to IRAS requests. IRAS may ask for further documents or a guarantee before approving the registration.
IRAS lists an estimated processing time of about 2 working days for a complete compulsory application and 10 working days for a complete voluntary application. Some applications may take up to 30 days, especially where information or supporting documents are incomplete.
See IRAS’s GST registration application guide before submitting.
When should the business start charging GST?
Start charging GST only from the effective registration date stated in IRAS’s approval letter.
The letter will provide:
- The GST registration number
- The effective date of registration
From that date, the business generally charges GST at the current rate of 9% on standard-rated supplies. Zero-rated and exempt supplies are treated differently.
Do not charge GST before the effective date. A non-registered business that wrongfully collects GST must disclose and return the amount to IRAS.
For a late compulsory application, IRAS will backdate the effective date to when the business should have been registered. For voluntary registration, the effective date is generally within 2 weeks from the approval letter and is not backdated for input-tax claims.
How does InvoiceNow affect a new GST registration?
GST registration and the GST InvoiceNow requirement are connected, but they are not the same process.
From 1 April 2026, every business applying for voluntary GST registration must comply with the GST InvoiceNow requirement. This means using an InvoiceNow-ready solution to transmit invoice data to IRAS.
New compulsory GST registrants come into the mandate from 1 April 2028.
The application form may ask for the business’s Peppol ID where InvoiceNow applies. The business should therefore review its accounting and invoicing setup before submitting a voluntary application.
Our InvoiceNow guide for GST-registered businesses explains the phased requirements and preparation steps. This article remains focused on whether and how to register for GST.
What happens if GST registration is late?
Late registration can be expensive because IRAS may backdate the registration to the date the business should have been registered.
The business will then need to:
- Account for GST on past taxable sales from the backdated effective date
- Pay that GST even if it was not collected from customers
- Correct its invoices and records where required
IRAS may also impose:
- A fine of up to S$10,000
- A penalty equal to 10% of the GST due
- Prosecution in serious cases
A business that discovers the error should disclose it when applying. IRAS generally waives the late-notification fine and penalties for a voluntary disclosure, but the backdated GST remains payable.
Do not delay simply because the business did not collect GST from customers. That does not remove the liability.
What changes after GST registration?
Once registered, the business becomes responsible for charging and accounting for GST correctly.
It will need to:
- Charge GST on standard-rated supplies from the effective date
- Issue compliant invoices and receipts
- Keep proper GST and accounting records
- File GST returns, including nil returns where there were no transactions
- Pay any GST due by the return deadline
- Keep its InvoiceNow setup current when the requirement applies
This guide does not cover the full GST return and accounting process. Businesses that need ongoing bookkeeping and GST support may refer to our accounting and compliance services.
Can the business cancel its GST registration later?
Yes, but cancellation is not automatic when turnover falls below S$1 million.
A business must apply within 30 days where it:
- Stops making taxable supplies and does not intend to make them again
- Ceases business
- Transfers the business as a whole
- Changes its legal form
A business may also apply voluntarily where it is no longer liable to remain registered. It must usually show that taxable turnover for the next 12 months will be S$1 million or less because of specific circumstances, and that it is not liable under reverse charge.
A voluntary registrant must remain registered for at least 2 years before applying to cancel.
Continue charging GST and filing returns until the effective cancellation date given by IRAS. See IRAS’s GST cancellation guide for the full requirements.
GST registration checklist
- Calculate taxable turnover for the latest calendar year.
- Exclude exempt, out-of-scope and capital-asset sales where appropriate.
- Monitor signed contracts, confirmed orders and recurring sales for the prospective test.
- Record the date when a supported forecast first exceeds S$1 million.
- Apply within the correct deadline.
- Decide whether voluntary registration makes commercial sense if registration is not compulsory.
- Complete the GST e-learning where required.
- Check Corppass access before starting the application.
- Prepare turnover records and supporting documents.
- Set up GIRO if applying voluntarily.
- Review whether the GST InvoiceNow requirement applies.
- Do not charge GST before the effective registration date.
- Update prices, invoices and accounting software before registration takes effect.
Frequently asked questions
What is the GST registration threshold in Singapore?
A business must generally register if its taxable turnover was more than S$1 million in the past calendar year, or if it reasonably expects taxable turnover to be more than S$1 million in the next 12 months.
Is the threshold based on revenue or profit?
It is based on taxable turnover, not profit. Business expenses are not deducted when checking the S$1 million threshold.
What is Singapore’s current GST rate?
The current GST rate is 9%. GST-registered businesses generally charge 9% on standard-rated supplies unless the sale is zero-rated or exempt.
Must a business register immediately when sales cross S$1 million?
Not always. Under the retrospective test, the business assesses turnover for the full calendar year and applies in January if it exceeded S$1 million. Immediate action is required where the prospective test applies because the business reasonably expects turnover to exceed S$1 million in the next 12 months.
Can a business register voluntarily below S$1 million?
Yes, if it qualifies. The business should first consider the 2-year minimum registration period, GIRO, compliance costs, customer profile, input-tax benefits and the GST InvoiceNow requirement.
Can a business charge GST while waiting for approval?
No. It may charge GST only from the effective registration date stated in IRAS’s approval letter.
Does a voluntary GST applicant need InvoiceNow?
Yes. Businesses applying for voluntary GST registration on or after 1 April 2026 must comply with the GST InvoiceNow requirement.
What happens if GST registration is late?
IRAS may backdate the registration. The business must account for GST on past sales even if it did not collect GST, and may face a fine of up to S$10,000 and a penalty equal to 10% of the GST due.
Can a voluntary registrant cancel immediately?
No. A voluntary registrant must generally remain GST-registered for at least 2 years before applying for cancellation.
Need help with GST registration and accounting setup?
Leftright Corporate can help review the registration basis, prepare the application and set up the accounting workflow needed after registration.
See our accounting and compliance services or digital accounting setup for more information.
