Who needs a UEN in Singapore, how to register with Inland Revenue Authority of Singapore (IRAS), what the number looks like, how to find or check one, and where it goes on your invoices.
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Updated for 2026
Last reviewed September 2026
What the UEN is
The UEN is the number Inland Revenue Authority of Singapore (IRAS) assigns to a taxpayer in Singapore. It follows you across every tax you deal with: GST, income tax and withholding. Businesses that pay you will ask for it before they release payment, because they report their suppliers to Inland Revenue Authority of Singapore (IRAS) by this number.
UEN: 9 or 10 characters (201912345A). GST number: usually the UEN or an M-prefixed number.
Who needs one
Individuals use their NRIC or FIN; companies and businesses use the UEN issued by ACRA; GST registration is separate.
How to register, step by step
Register the business or company with ACRA via BizFile+; the UEN is issued at registration and is your tax reference.
Register for GST on myTax Portal within 30 days once taxable turnover exceeds S$1 million.
Set up Corppass to transact with IRAS.
How to find or check a UEN
Check a GST registration on the IRAS GST Registered Business Search.
Where it goes on your paperwork
In the invoice header next to your business name, and in the client block when the client is a registered business. Quotations and purchase orders carry it too, so the client's accounts team can match documents. The Singapore invoice generator has a UEN field in both blocks.
Questions people ask
Does it cost anything to get a UEN?
Registration with Inland Revenue Authority of Singapore (IRAS) is normally free. Agents charge for filling in the same form; pay one only if you want the time saved.
Can I invoice without a UEN?
You can write the document, but many clients will not pay an invoice that has no UEN, and you cannot charge GST without being registered. Register first; it is usually quick.
Is the UEN the same as GST registration?
Not necessarily. The UEN identifies you as a taxpayer; GST registration is a separate status you take on when turnover passes the threshold or you opt in. Some countries use one number for both, others issue a separate GST number.
How long does registration take?
Online registrations are often instant or take a few days; applications that need a visit or document checks take longer. Start before you need to send your first invoice.
Written from published tax-authority guidance and reviewed on 2026-09-03. Everything here is indicative rather than a ruling on your circumstances, and rules change. Confirm anything you rely on with Inland Revenue Authority of Singapore (IRAS) before acting on it, and tell us if you find something out of date so we can correct it.
This guide explains the rules in general terms and is not tax advice for your circumstances. Confirm your position with a qualified adviser or with Inland Revenue Authority of Singapore (IRAS).
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Invoices, quotations, purchase orders, credit notes and waybills in SGD, with GST and the UEN on the document. Plus a GST calculator and a salary tax calculator. Everything runs in your browser and nothing is uploaded.