GST Registration in Singapore 2026: When You Must Register and How It Works
You must register for GST in Singapore when your business’s taxable turnover exceeds S$1 million in a 12-month period, or when you have reasonable grounds to expect it will exceed that threshold in the next 12 months. The current GST rate is 9%. Failure to register on time can result in IRAS backdating your registration and requiring you to pay GST on past sales — out of your own pocket, even if you did not collect it from customers.
HeySara’s accounting and tax team helps businesses assess their GST position accurately and manage registration and ongoing filing without stress.
What Is GST?
Goods and Services Tax (GST) is Singapore’s consumption tax, levied at 9% on most goods and services supplied within Singapore and on goods imported into Singapore. GST was increased from 8% to 9% with effect from January 1, 2024, and there are no further rate changes announced for 2026 or 2027 at this time.
Businesses registered for GST act as collection agents on behalf of IRAS — charging output tax on sales and claiming input tax credits on qualifying purchases, remitting the net difference to IRAS quarterly.
The Two Triggers for Compulsory GST Registration
Trigger 1: Retrospective Basis If your taxable turnover in any calendar year (or financial year, for the purpose of this assessment, the rolling 12-month period ending 31 December) exceeds S$1 million, you must register for GST within 30 days of the year ending.
Trigger 2: Prospective Basis If at any time you have reasonable grounds to believe your taxable turnover will exceed S$1 million in the next 12 months (for example, you have just signed a major contract), you must register within 30 days of forming that belief — before the revenue is actually earned.
Both bases require active monitoring of your taxable revenue. Many businesses miss the prospective trigger by focusing only on past turnover.
What counts as taxable turnover?
Standard-rated supplies (9% GST) and zero-rated supplies (0% GST, e.g., exported goods, international services) both count toward the threshold. Exempt supplies (financial services, sale and lease of residential properties) and out-of-scope supplies do not count.
Voluntary GST Registration
Businesses below the S$1 million threshold may voluntarily register for GST. The main reason to do so is to claim input tax credits — reclaiming the 9% GST you pay on qualifying business purchases (rent, equipment, professional services) from IRAS.
Voluntary registrants must: – Remain registered for at least 2 years before deregistering – Comply with all GST filing and record-keeping obligations – Use InvoiceNow-ready software (see below)
2026 Update: InvoiceNow Requirements
As part of Singapore’s push for digital tax administration, IRAS has introduced phased requirements for GST-registered businesses to use InvoiceNow-compliant software to transmit invoice data digitally:
- From November 1, 2025: All new voluntary GST registrants must use InvoiceNow-ready software
- From April 2026: This requirement extends to all new voluntary registrants
InvoiceNow uses the Peppol network to transmit structured invoice data directly between companies and to IRAS. If you are considering voluntary registration in 2026, ensure your accounting software is InvoiceNow-certified before applying.
The Consequences of Late Registration
IRAS treats late registration seriously:
- Your registration is backdated to the date you should have registered
- You must pay GST on all past sales from the effective date — even if you did not charge customers
- A fine of up to S$10,000 may be imposed
- Interest charges on outstanding GST
The most common scenario: a company crosses S$1 million in turnover in June but only realises in November. IRAS backtracks the registration to July, and the company owes 5 months of output tax from its own margin.
How to Register for GST
- Complete an e-Learning course on GST via IRAS’s myTax Portal (mandatory for all new registrants)
- Submit the GST registration application via myTax Portal
- Set up a GIRO account linked to IRAS for GST payment and refunds
- Ensure your accounting software is InvoiceNow-ready (for voluntary registrants)
- IRAS will issue a GST registration number and effective date of registration
- Update all tax invoices to display your GST registration number from the effective date
GST Filing: Quarterly F5 Returns
All GST-registered businesses must file quarterly GST returns (Form F5) within 1 month of the end of each accounting period. Returns are submitted via myTax Portal. Late filing attracts penalties.
HeySara’s Accounting and Tax Services
HeySara’s accounting team proactively monitors your turnover trajectory, advises on the correct timing for GST registration, prepares and files your quarterly F5 returns, and ensures your invoicing is GST-compliant. For businesses approaching the S$1 million threshold in 2026, we recommend a GST readiness assessment well in advance.
