GST Registration in Singapore 2026: The S$1M Threshold, InvoiceNow & Deadlines

Last Updated: June 2026

Key Takeaways

• You must register for GST if your taxable turnover exceeded S$1 million in the past calendar year (retrospective basis) or you reasonably expect it to exceed S$1 million in the next 12 months (prospective basis).
• For the retrospective basis using calendar year 2025, you must apply by 30 January 2026, with registration effective 1 March 2026.
• Since 1 July 2025, businesses registering on the prospective basis get a two-month grace period to start charging GST — but you must still apply within 30 days of your forecast date.
• From 1 April 2026, all new voluntary GST registrants must transmit invoice data to IRAS through the InvoiceNow (Peppol) network. The requirement extends to all GST-registered businesses by April 2031.
• Registering late triggers backdated GST, a 10% penalty, and a fine of up to S$10,000.

Do you have to register for GST? In short: if your business’s taxable turnover has crossed S$1 million over the past 12 months, or you can reasonably forecast that it will within the next 12 months, GST registration is compulsory — not optional. The current GST rate is 9%. Miss the window and the Inland Revenue Authority of Singapore (IRAS) can backdate your liability and impose penalties.

This guide pulls together everything a Singapore business owner needs in one place: how to confirm whether you’ve crossed the threshold, the new 2025 grace period, the InvoiceNow e-invoicing deadlines that catch most new companies off guard, the step-by-step registration process, and the penalties for getting it wrong.

What Is GST — and Why Registration Is Not Optional

Goods and Services Tax (GST) is a consumption tax levied on the supply of goods and services in Singapore and on the import of goods. It is administered by IRAS and currently charged at 9% (the rate rose to 9% on 1 January 2024).

Once your business crosses the registration threshold, charging and accounting for GST stops being a choice. You are legally required to register, charge GST on your taxable supplies, file returns, and remit what you collect to IRAS. The cost of “not getting around to it” is real: backdated tax, penalties, and a compliance review.

The Magic Number: How to Check If You Must Register

Compulsory registration is tested in two ways. You only need to satisfy one of them to be liable.

Retrospective Basis (“Looking Back”)

Add up your taxable turnover for the calendar year (1 January to 31 December). If it exceeded the S$1 million registration threshold, you are liable.

• Example (2025 calendar year): If your taxable turnover for 1 Jan – 31 Dec 2025 crossed S$1 million, you must apply by 30 January 2026, and your registration takes effect on 1 March 2026.

Prospective Basis (“Looking Forward”)

If at any point you can reasonably expect your taxable turnover to exceed S$1 million in the next 12 months — for example, after signing a major contract — you are liable on a prospective basis. You must apply for GST registration within 30 days of that forecast date.

What Counts Toward the S$1 Million

“Taxable turnover” is the value of your standard-rated and zero-rated supplies. When testing the threshold, exclude:

• Sales of capital assets (for example, disposing of business equipment or vehicles)
• Inter-company loans
• Exempt supplies and out-of-scope supplies

Getting this calculation wrong — in either direction — is one of the most common and costly registration mistakes.

New in 2025: The Two-Month Grace Period for Prospective Registration

Announced by the Second Minister for Finance on 28 February 2025, businesses that become liable on the prospective basis now receive a two-month grace period to begin charging GST, where the forecast date falls on or after 1 July 2025. This is an extension from the previous one-month period.

How it works in practice:

• You must still apply within 30 days of your forecast date.
• Your registration becomes effective two months from the forecast date.
• Example: If your forecast date is 2 September, you are registered effective 2 November.

One critical caveat: the grace period only delays when you start charging GST. It does not delay your filing obligations. From your effective date of registration you must keep proper records and file your GST F5 returns on time. Treating the grace period as a holiday from compliance is a recipe for penalties.

The InvoiceNow (Peppol) E-Invoicing Mandate

This is the rule most newly incorporated companies miss. IRAS is phasing in a mandatory requirement to transmit invoice data to IRAS through the InvoiceNow network — Singapore’s nationwide e-invoicing system built on the international Peppol standard.

The phased timeline:

• Since 1 November 2025: Newly incorporated companies that register for GST voluntarily must transmit invoice data via InvoiceNow. “Newly incorporated” means incorporated within 6 months of submitting the GST registration application.
• From 1 April 2026: All new voluntary GST registrants must transmit invoice data to IRAS via InvoiceNow, regardless of incorporation date or business structure.
• By April 2031: At Committee of Supply 2026, IRAS announced the requirement will extend to all GST-registered businesses — not just new registrants.

To comply, you transmit prescribed invoice data to IRAS using an IMDA-accredited InvoiceNow-Ready Solution (many common accounting platforms qualify), by the earlier of the day you file your GST return or the return’s due date.

Support available: The Government is offering transitional funding to offset onboarding costs — up to S$1,000 for SMEs and up to S$5,000 for larger businesses — and SMEs can use InvoiceNow-Ready Solutions free until March 2031. The practical takeaway: if you are planning to register for GST in 2026, plan your e-invoicing setup at the same time to avoid expensive rework.

How to Register for GST: The 5-Step Process

Registration is done through the IRAS myTax Portal. The process has five sequential steps:

1. Confirm your eligibility and basis. Establish whether you are registering on the retrospective or prospective basis, or voluntarily.
2. Prepare and submit Form GST F1. Complete the GST F1 application and attach supporting documents (financial statements, business contracts, and the relevant declarations).
3. Complete the IRAS e-Learning course (voluntary registrants). Designated directors or staff of voluntary applicants must complete a short IRAS e-learning course on GST obligations before registering.
4. File via myTax Portal using CorpPass. Submit the application electronically with your company’s CorpPass credentials.
5. Receive your registration notification. On approval, IRAS issues a notification confirming your effective date of registration and your GST registration number.

Note: Form GST F1 is the application to register. Once registered, you file your periodic GST F5 returns — these are two different forms that are easy to confuse.

Should You Register Voluntarily? (Revenue Under S$1 Million)

If you are below the S$1 million threshold, you can still register voluntarily. It can be worthwhile, but it comes with strings attached.

Potential benefits:

• Claim input tax credits on your business expenses (rent, equipment, professional fees).
• Enhanced credibility with corporate and government customers who expect GST-registered suppliers.
• Cash-flow advantage for exporters, whose sales are typically zero-rated while their input tax is recoverable.

Commitments to weigh:

• A minimum two-year registration commitment — you cannot register to recover a one-off cost and then deregister.
• You must comply with the InvoiceNow requirement (mandatory for new voluntary registrants from 1 April 2026).
• Ongoing compliance: charging GST correctly, issuing tax invoices, and filing returns on time.

Voluntary registration suits export-oriented businesses and those with significant recoverable input tax. For a small domestic business selling mainly to consumers, the compliance burden may outweigh the benefit.

What If You Register Late? The Penalties

IRAS treats late registration seriously. If you should have registered but didn’t, you can face:

• Backdated GST liability — you may have to account for 9% GST on all taxable sales from the date you were required to register, even if you never charged your customers.
• A 10% penalty on the GST due.
• A fine of up to S$10,000.

The backdated liability is often the most painful part: the GST comes out of your own pocket if you can no longer recover it from past customers. (Source: IRAS — consequences of registering late.)

Staying Compliant After Registration

Registration is the start, not the end. Once registered you must:

• Charge GST at 9% on your standard-rated supplies.
• File GST F5 returns for each accounting period (usually quarterly) and pay any GST due by the deadline.
• Issue valid tax invoices and keep proper records for at least five years.
• Transmit invoice data via InvoiceNow once you are within scope.

Late filing, under-reporting, or poor records can trigger an IRAS audit and further penalties.

Common GST Registration Mistakes to Avoid

• Assuming the grace period delays your returns. It only delays when you start charging GST — your F5 filing and record-keeping obligations start from your effective date.
• Charging GST before your effective date, or failing to charge after the window closes. Both create problems at filing time.
• Ignoring InvoiceNow. Companies registering near the November 2025 and April 2026 deadlines often forget the e-invoicing setup until it is urgent.
• Miscalculating taxable turnover. Forgetting to exclude capital asset sales and inter-company loans — or including exempt supplies — leads to registering at the wrong time.

Frequently Asked Questions

Do I have to register for GST in Singapore? You must register if your taxable turnover exceeded S$1 million in the past calendar year (retrospective basis) or you reasonably expect it to exceed S$1 million in the next 12 months (prospective basis). Below S$1 million, registration is voluntary.

What is the GST registration threshold in Singapore? The threshold is S$1 million in taxable turnover. It is tested on both a retrospective (past 12 months) and prospective (next 12 months) basis. The current GST rate is 9%.

What is the two-month grace period for GST registration? For businesses liable on the prospective basis with a forecast date on or after 1 July 2025, registration takes effect two months from the forecast date, giving you time to prepare to charge GST. You must still apply within 30 days of the forecast date, and your filing obligations are not delayed.

When does the InvoiceNow GST requirement start? Newly incorporated companies registering voluntarily have been required to use InvoiceNow since 1 November 2025. From 1 April 2026, all new voluntary GST registrants must transmit invoice data to IRAS via InvoiceNow. The requirement extends to all GST-registered businesses by April 2031.

What happens if I register for GST late? IRAS can backdate your GST liability to the date you should have registered (9% on applicable sales), impose a 10% penalty on the GST due, and levy a fine of up to S$10,000.

Don’t Guess Your Revenue — Get a GST Liability Assessment

GST registration is a legal and financial responsibility, not a formality. The threshold test, the prospective grace period, and the InvoiceNow deadlines all have hard dates — and the penalty for getting them wrong comes out of your own pocket.

Excellence Singapore’s GST Liability Assessment verifies whether you’ve crossed the threshold, checks your exemption eligibility, confirms your InvoiceNow software readiness, and handles the Form GST F1 application end to end. If you are approaching S$1 million in turnover, or planning a voluntary registration in 2026, talk to us before the deadline finds you.

All figures in this guide are sourced from IRAS via the inline links cited throughout.