Quick Answer
In Singapore you only charge GST once your taxable turnover exceeds S$1 million and you register with IRAS. A compliant tax invoice must be titled Tax Invoice and show your GST registration number, the 9% GST as a separate line, and the total payable. Unregistered businesses must not charge GST. The rate is current as of 2026.
In Singapore you only charge GST once your taxable turnover passes S$1 million and you register with IRAS, and a compliant tax invoice must be titled "Tax Invoice" and show your GST registration number with 9% GST as a separate line. This guide covers everything a Singapore freelancer or small business owner needs to know about GST and invoicing: whether you need to register, what a compliant tax invoice must include, when to issue it, how to handle the GST number versus UEN distinction, record-keeping obligations, and the mistakes that create problems at audit time.
Do You Need to Charge GST?
GST registration becomes compulsory when your taxable turnover exceeds S$1 million over any rolling 12-month period. That is not a calendar-year threshold; it applies to any consecutive 12-month window. If you are approaching that level, IRAS requires you to register within 30 days of the date you first become aware that you will exceed it.
Below S$1 million, registration is voluntary. Some businesses register voluntarily because their clients are GST-registered and can claim back the input tax anyway, making the GST cost neutral for corporate buyers. Others stay unregistered to keep pricing simpler and avoid quarterly filing obligations. Both approaches are legitimate depending on your client base and revenue profile.
The practical test: add up your taxable turnover for the past 12 months. If it is comfortably below S$900,000, you are well within the threshold. If it is approaching S$1 million, consult an accountant or check the IRAS website directly before proceeding.
The 2026 GST Rate
Singapore's GST rate is 9%, in effect since 1 January 2024. When calculating GST for a client, apply 9% to the total taxable amount before tax. A S$1,000 service fee carries S$90 GST, for a total of S$1,090.
When Must You Issue a Tax Invoice?
GST-registered businesses must issue a tax invoice within 30 days of the time of supply. The time of supply is generally the earliest of: the date the goods or services are delivered, the date payment is received, or the date the invoice is issued. For most service businesses, this means issuing the tax invoice on or very shortly after delivery of the work.
For long-running projects or recurring services, IRAS has specific rules for progressive billing and periodic supplies. If your engagement spans multiple months or involves milestone-based billing, check iras.gov.sg for the time of supply rules that apply to your contract type.
Need to generate a GST-compliant tax invoice?
Select "Singapore GST (9%)" in the tax settings. The calculation is automatic. Create a Tax Invoice FreeWhat GST-Registered Businesses Must Include on Their Tax Invoice
IRAS requires nine specific fields on a full tax invoice for any supply where the total (including GST) exceeds S$1,000. Missing any field means the document does not qualify as a valid tax invoice, and your client cannot use it to claim input tax credit.
| Required field | What to include |
|---|---|
| Document title | The words "Tax Invoice" displayed prominently |
| Invoice number | A unique sequential number, never reused |
| Date of issue | The date the invoice is issued |
| Your details | Your name or company name, address, and GST registration number |
| Customer details | Customer name and address |
| Description of supply | What goods or services are being supplied |
| Quantity and unit price | For goods: quantity and unit price. For services: scope description. |
| Amount excluding GST | Subtotal before GST is applied |
| GST amount | GST at 9% as a separate line, plus total including GST |
IWantFreeInvoice.com includes all nine fields in the default invoice form. Enable the GST toggle, select "Singapore GST (9%)", enter your GST registration number once, and the tool handles the layout and arithmetic automatically.
How to Show GST Correctly
GST must appear as a separate line item. Quoting an all-in price and writing "GST included" without a breakdown is not compliant, and it prevents your client from claiming input tax. The correct format:
Subtotal: S$1,000.00
GST (9%): S$90.00
Total: S$1,090.00
GST Registration No: M12345678X
This format is unambiguous. Your client's finance team can claim back the S$90 as input tax without needing to request a corrected invoice.
Simplified Invoice vs Full Tax Invoice
IRAS allows a simplified tax invoice for supplies where the total (including GST) is S$1,000 or less. The simplified format requires fewer fields: you do not need to include the customer's name and address, and you may show just the GST rate rather than the exact GST amount.
| Feature | Simplified (under S$1,000) | Full (over S$1,000) |
|---|---|---|
| Customer name and address | Not required | Required |
| GST shown as | Rate or amount (either) | Separate amount, mandatory |
| "Tax Invoice" title | Required | Required |
| Your GST registration number | Required | Required |
Your GST Registration Number versus Your UEN
These two numbers are often confused. Your UEN (Unique Entity Number) is your business registration number issued by ACRA. Your GST registration number is issued separately by IRAS when you register for GST. For many businesses the numbers are related, but they are not identical and serve different purposes.
Your GST registration number is the one that must appear on every tax invoice. If a client asks for your "GST number," they mean the IRAS-issued registration number, not your UEN. You can find it in your GST registration approval letter or via myTax Portal at mytax.iras.gov.sg.
If you are not GST-registered, you still have a UEN from ACRA if you are a registered business. Including your UEN on invoices is good practice and is required by some corporate clients' procurement processes, but it does not mean you are charging GST. Never add a GST line to an invoice just because you have a UEN. If you are trading as a sole proprietor, the guide to invoicing as a sole proprietor in Singapore covers how your business name and UEN should appear alongside your personal details on each invoice.
Correcting a Mistake on a Tax Invoice
If you issue a tax invoice with an error, you cannot simply delete or overwrite it. Issue a credit note to cancel the original invoice, then issue a corrected tax invoice with a new sequential number. Keep all three documents (original invoice, credit note, corrected invoice) together. IRAS may ask to see the full paper trail if the amounts were reported on a GST return.
What If You Are Not GST-Registered?
Do not charge GST and do not show GST on your invoice. If you are not registered, you have no authority to collect GST. Collecting it and not remitting it to IRAS is an offence under the GST Act. If a client asks whether your price is inclusive or exclusive of GST, state that your services are not subject to GST as you are not a registered business. You may also add a line reading "GST: Not applicable" on your invoice to prevent the question from arising. GST registration status is separate from income tax, and the Singapore freelancer tax guide explains how the income on your invoices is taxed each year regardless of whether you charge GST.
Record Keeping Requirements
GST-registered businesses must keep all tax invoices for a minimum of five years from the date of issue. This applies to invoices you issue to clients and invoices you receive from suppliers. Records can be kept in electronic form, provided they are complete and accessible for IRAS audits.
Good practice: file each invoice alongside the corresponding payment confirmation and, where applicable, the client's purchase order or contract. If an invoice is ever disputed or an IRAS query arises, having the full chain of documents in one place resolves the issue quickly.
Common GST Invoice Mistakes
What Else Do People Ask?
What is a GST invoice in Singapore?
A GST invoice, which IRAS calls a tax invoice, is the document a GST-registered business issues to show the Goods and Services Tax charged on a sale. It must be titled Tax Invoice and show the supplier's GST registration number and the 9 percent GST on a separate line. A GST-registered customer uses it to claim back input tax, so every required field has to be there.
Who needs to issue a GST invoice in Singapore?
Only GST-registered businesses issue tax invoices. Registration is compulsory once your taxable turnover passes 1 million dollars over any rolling 12-month period, and voluntary below that. If you're not registered, you must not issue a tax invoice or charge GST. You issue an ordinary invoice with no GST line instead.
What is the GST rate in Singapore in 2026?
The GST rate in Singapore is 9 percent, in effect since 1 January 2024, and Budget 2026 confirmed no change. You apply 9 percent to the pre-tax value of the supply, so a 1,000 dollar fee carries 90 dollars of GST and a total of 1,090 dollars.
What is a simplified tax invoice?
A simplified tax invoice is a shorter version IRAS allows when the total including GST is 1,000 dollars or less. It still needs the Tax Invoice title and your GST registration number, but you can skip the customer's name and address and show GST more loosely. Above 1,000 dollars, the full set of particulars applies.
Do I need a GST invoice if I am not GST-registered?
No. If you're not GST-registered, you issue a normal invoice, not a tax invoice, and you don't add any GST. Using the words Tax Invoice or charging GST while unregistered isn't allowed and is an offence under the GST Act. You can still show your UEN, just leave GST off the document.
To work out the actual figures, the free tax calculators at AsiaCalc cover Singapore and Malaysia income tax, GST, and more.