GST Registration in Singapore: 2026 Guide

Quick answer: GST registration in Singapore becomes compulsory once your taxable turnover exceeds S$1 million — either over the past calendar year (retrospective basis) or where you reasonably expect to exceed it in the next 12 months (prospective basis). The current GST rate is 9%. If you cross the threshold on the retrospective basis, you must apply by 30 January and registration takes effect on 1 March; on the prospective basis you must register within 30 days of forming that expectation. Businesses below S$1 million can register voluntarily. From 1 April 2026, new voluntary registrants must transmit invoice data to IRAS via the InvoiceNow (Peppol) network.

When is GST registration compulsory?

You must register for GST if your taxable turnover crosses the S$1 million threshold on either of two bases:

• Retrospective basis: your taxable turnover for the calendar year (1 January to 31 December) exceeded S$1 million. You must apply by 30 January of the following year, and your registration takes effect on 1 March.
• Prospective basis: at any point you have reasonable grounds to expect your taxable turnover will exceed S$1 million in the next 12 months — for example, after signing a major contract. You must register within 30 days of forming that expectation, before the revenue is even earned.

“Taxable turnover” means the total value of your standard-rated and zero-rated supplies — broadly your taxable sales, excluding exempt supplies and out-of-scope sales. Failing to register on time can result in penalties and backdated GST liability, so monitor your rolling turnover closely as you approach the threshold.

Voluntary registration — and when it makes sense

If your turnover is below S$1 million you can still register voluntarily. This can be worthwhile if most of your customers are GST-registered businesses (who can claim the GST back), or if you incur significant input GST on purchases that you would like to recover. The trade-offs are the administrative burden of quarterly GST returns and a commitment to stay registered for at least two years. Voluntary registrants must also comply with conditions set by IRAS, including, from 1 April 2026, transmitting invoice data through the InvoiceNow network.

The 9% rate and the InvoiceNow mandate

Singapore’s GST rate is 9%, having risen from 8% to 9% on 1 January 2024. A significant 2026 change affects how registrants report: from 1 April 2026, newly-incorporated companies and other new voluntary GST registrants must adopt InvoiceNow — Singapore’s nationwide e-invoicing network built on the Peppol standard — to transmit invoice data to IRAS. If you are planning a voluntary registration, factor in setting up an InvoiceNow-ready accounting solution.

How to register with IRAS

1. If registering voluntarily, complete IRAS’s required GST e-Learning course (“Overview of GST”) — the company director, sole proprietor or partner, or the person preparing the GST returns, must do so unless an exemption applies.
2. Prepare your supporting documents and turnover figures.
3. Submit the GST registration application through IRAS’s myTax Portal using your Corppass.
4. Set up GST-compliant invoicing and, where required, an InvoiceNow-ready solution.
5. Once approved, charge 9% GST on taxable supplies, issue tax invoices, and file your GST returns (usually quarterly).

For support with GST registration and returns, discuss your requirements with our accounting and taxation teams. The scope is agreed around your business.

Not sure whether — or when — to register for GST?
Assembly Works advises on GST registration and supports the preparation of quarterly returns. Contact us to discuss your circumstances. See our taxation service or contact us.