GST and invoicing in Singapore (2026): rates and InvoiceNow

Singapore’s Goods and Services Tax (GST) is a value added tax on goods and services supplied in Singapore and on imports. A GST-registered business charges GST on its sales, claims the GST on its business purchases and pays the difference to the Inland Revenue Authority of Singapore (IRAS). The system is simple by international standards, with one rate and quarterly returns, but it is now adding InvoiceNow, a phased requirement to send invoice data to IRAS. This guide covers what a small business needs to know in 2026. Figures are as of October 2026.

GST at a glance

• Rate: 9% since 1 January 2024. GST was introduced on 1 April 1994 at 3%, and was 8% in 2023.
• Zero-rated (0%): exports of goods and international services, subject to conditions. You still claim the GST on related purchases.
• Exempt: prescribed financial services, the sale and rental of residential property, digital payment tokens, and investment precious metals. No GST is charged and the related input tax is generally not claimable.
• Overseas suppliers: under overseas vendor registration, foreign businesses selling remote services or imported low-value goods to non-registered customers in Singapore must register when those sales pass S$100,000 in 12 months and their global turnover is at least S$1 million.

Who must register for GST

You must register when your taxable turnover (standard-rated and zero-rated supplies, not exempt supplies or sales of capital assets) passes S$1 million, on either test:

• Retrospective view: if your taxable turnover for the calendar year (1 January to 31 December) was more than S$1 million, apply between 1 and 30 January of the following year; you are registered from 1 March.
• Prospective view: if at any time you can reasonably expect more than S$1 million in the next 12 months, for example because of signed contracts or confirmed orders, apply within 30 days of that forecast. If the liability arises on or after 1 July 2025, you are registered two months after the forecast date, which gives you time to start charging GST.

Voluntary registration: you can register below the threshold if you make taxable supplies, or plan to and can show firm intentions. Voluntary registrants must stay registered for at least two years, and since 1 April 2026 they must also meet the InvoiceNow requirement from the start.

Your GST registration number is usually your Unique Entity Number (UEN), for example 123456789A, or a separate number such as M2-1234567-K.

GST returns and payment

• Return: the GST F5, normally for each quarter. You file a “Nil” return even when you had no business activity.
• Deadline: the return and the payment are due one month after the end of the accounting period:

• Extensions are generally not granted; IRAS lists staff leave or year-end closing among the reasons it will not accept.
• Errors in earlier returns are corrected in the next F5 when conditions are met, or with a GST F7.

Tax invoices: what they must show

You must issue a tax invoice to a GST-registered customer within 30 days of the time of supply, because it supports the customer’s input tax claim. You do not need one for zero-rated or exempt supplies, or for customers that are not GST-registered. A tax invoice must show:

Show exempt, zero-rated and other supplies separately, with the gross amount for each type.

• Simplified tax invoice: when the total including GST is S$1,000 or less, you need only your name, address and GST registration number, the date, an identifying number, the description, the total including GST, and a statement such as “price payable includes GST”.
• Receipts: for customers who are not GST-registered you may issue serially numbered receipts showing the date, your business name and GST number, the total including GST, and “Price payable includes GST”. You must issue one if the customer asks.
• Foreign currency: when you invoice in a foreign currency, the total excluding GST, the total including GST and the GST payable must also be shown in Singapore dollars, converted at an exchange rate approved for GST.
• Rounding: you can apply 9% to each line or to the total, but you must use the same method consistently.
• Credit notes: to correct a mistake or give credit (returns, waived charges, discounts on past sales), show a serial number, date, your and your customer’s details, the reason, the goods or services and the amounts credited, the rate and GST credited, and ideally the number and date of the original tax invoice. Debit notes are only for transactions without GST or to record credits due from suppliers.
• Keeping records: keep the tax invoices you issue and receive for at least five years.

InvoiceNow: e-invoicing and the GST requirement

InvoiceNow is Singapore’s nationwide e-invoicing network based on the Peppol standard, introduced by the Infocomm Media Development Authority (IMDA) in 2019. Under the GST InvoiceNow Requirement, GST-registered businesses must send their invoice data to IRAS using an InvoiceNow-Ready Solution, in phases:

“Total annual supplies” means standard-rated, zero-rated and exempt supplies (box 4 of the GST return) for the accounting periods ending in calendar year 2025. From mid-2026 IRAS notified businesses registered before 2026 of their own implementation date. Overseas vendors and businesses registered only because of the reverse charge are excluded. Grants are available, including a GST InvoiceNow Transition Grant, and free basic solution packages are offered until 31 March 2031.

Worked example in Singapore dollars

A GST-registered consultancy has this quarter (July to September):

GST payable: S$3,600 output tax minus S$1,080 input tax = S$2,520, filed and paid by 31 October.

Paying GST late

• 5% penalty on the tax not paid by the due date, or on IRAS’s estimate if the return is not filed.
• Additional 2% a month if the tax remains unpaid 60 days after the 5% penalty, up to a total of 50% of the unpaid tax.
• IRAS can also appoint agents such as your bank to collect the tax, and stop sole proprietors and partners from leaving Singapore.

For your own customers, set clear payment terms and follow up promptly; our guide on getting paid faster shows how.

Common mistakes

1. 1Watching only the calendar year. The prospective test applies as soon as you can reasonably expect more than S$1 million in the next 12 months.
2. 2Charging GST before you are registered, or continuing to issue invoices without GST after your registration date.
3. 3Issuing a simplified tax invoice above S$1,000.
4. 4Converting foreign-currency invoices with a rate IRAS does not accept, or not showing the GST in Singapore dollars.
5. 5Assuming InvoiceNow can wait: if you register voluntarily, the requirement applies from your registration.
6. 6Expecting an extension to the one-month filing deadline.

How Clientlly helps

Clientlly numbers your invoices sequentially per series and puts Singapore’s 9% rate on every invoice, with credit notes linked to the original invoice. You can invoice overseas clients in multiple currencies, send the PDF in your client’s language with a card payment link, see when it was opened and let automatic reminders go out 3, 14 and 30 days after the due date. Scanned receipts have the GST read automatically, sales and purchase tax books are kept per rate, including zero-rated exports and reverse charge, and tax reports with Excel and PDF exports are ready for you and your accountant. See invoicing and accounting.

Clientlly is not an InvoiceNow-Ready Solution and is not connected to the Peppol network or IRAS. When the GST InvoiceNow Requirement applies to you, you need an IMDA-accredited InvoiceNow-Ready Solution or Access Point to send your invoice data.