UIN Under GST: Unique Identification Number Explained

Most people who deal with GST never meet a UIN. Then a foreign embassy, a UN agency or a development bank places an order, hands over a 15-character number that looks almost like a GSTIN, and your billing system rejects it. That number is a Unique Identity Number. It exists so that bodies which are not meant to bear Indian GST can buy normally, pay the tax at the till, and get it back later. This post covers who gets one, how it differs from a GSTIN, how the refund works, and what you need to change if you are the supplier or the developer whose form just said "invalid GSTIN".

What a UIN is, and why it exists

GST is collected at the point of supply. A shop selling furniture to an embassy has no way of zero-rating that sale on the spot, and asking every supplier to work out which diplomatic privileges apply to which customer would be unworkable. So the law does the opposite: the supplier charges GST as normal, and the privileged buyer recovers it afterwards.

To recover it, the buyer needs an identity on the GST system that invoices can be matched to. That is the UIN. The statute calls it a "Unique Identity Number"; you will see "Unique Identification Number" just as often, and both mean the same thing.

The key point is what a UIN is not. It does not make the holder a taxpayer. A UIN holder does not charge GST, does not file GSTR-3B, and does not claim input tax credit. It receives supplies and files a statement of them. If you want the full picture of how the ordinary GSTIN works by comparison, read GSTIN format explained.

Who is issued a UIN under Section 25(9)

Section 25(9) of the CGST Act lists the bodies that are granted a UIN rather than a normal registration:

• Specialised agencies of the United Nations, and multilateral financial institutions and organisations notified under the United Nations (Privileges and Immunities) Act, 1947.
• Consulates and embassies of foreign countries in India.
• Any other person or class of persons notified by the Commissioner. This is the catch-all that lets the government extend UIN treatment to further bodies without amending the Act.

In practice, the entitlement of an embassy or consulate is tied to diplomatic reciprocity and is administered with the Ministry of External Affairs, so the scope of what a particular mission can claim back is not identical across countries. The lists of notified organisations change from time to time; confirm current coverage on cbic-gst.gov.in rather than relying on a list copied into a blog.

On the portal, a UIN holder shows up with its own taxpayer type, distinct from a regular taxpayer, composition dealer or non-resident. The guide to GST taxpayer types covers how those labels read in a lookup result.

How a UIN is obtained: Form REG-13

The application is made in Form GST REG-13 on the GST portal, under the rules on assignment of a UIN (Rule 17 of the CGST Rules). The applicant supplies its identifying details and those of an authorised signatory. Once the application is approved, the UIN is issued and the holder can log in to file statements and refund applications.

Missions and agencies usually route this through their administrative or finance office, often with a local tax practitioner. If you are a supplier, none of this is your paperwork, but it explains why a new mission sometimes cannot give you its UIN on day one: the number simply may not have been issued yet.

How a UIN is structured

A UIN is 15 characters long, the same length as a GSTIN, and it occupies the same field on invoices and in GSTR-1. That is where the resemblance ends. A GSTIN is a state code, the holder's 10-character PAN, an entity number, a literal Z and a check character. A UIN holder generally has no Indian PAN to build from, so its middle section follows a different scheme, and published examples do not carry the Z in position 14.

Commonly cited examples begin with a two-digit state code, followed by characters that encode things such as a year and a country or organisation code, then a serial number. The pattern below is illustrative only: it shows the general shape reported for UINs, not an official position-by-position specification.

Illustrative UIN (not an official specification):

0717UNO00157UNO
^^              two-digit state code, as in a GSTIN
  ^^^^^^^^^^^^^ year / country or organisation code / serial / suffix
                (not a PAN, and no fixed 'Z' at position 14)

We are deliberately not assigning meaning to each position. The layout of the non-PAN part is not published in the way the GSTIN layout is, and you should not build logic that depends on it. The safe assumptions are the ones in the table below.

How UIN holders get GST refunded

The refund entitlement comes from Section 55 of the CGST Act, which lets the government notify bodies such as UN agencies and embassies as entitled to a refund of tax paid on notified supplies of goods or services received by them. The mechanics are in Rule 95 of the CGST Rules.

The sequence runs like this:

1. The UIN holder buys from a registered supplier and pays GST on the invoice as any customer would.
2. The supplier reports the invoice in GSTR-1 against the UIN.
3. The UIN holder files GSTR-11, its statement of inward supplies for the period.
4. It applies for the refund in Form GST RFD-10, which Rule 95 provides for on a quarterly basis.
5. The officer processes the claim and the refund is paid to the holder's bank account.

Rule 95 attaches conditions to the claim. The supply must come from a registered person against a tax invoice, and the invoice must carry the holder's name and UIN. There are further conditions, including a minimum value per invoice and, for diplomatic missions, the limits of what the Ministry of External Affairs allows under reciprocity. These details have been amended over the years, so read the current Rule 95 on cbic-gst.gov.in before advising on a specific claim.

The general refund process for everyone else, including the RFD-01 route and the "relevant date" concept, is covered in the GST refund process guide. GSTR-11 itself sits in the full list of GST returns alongside the ones regular taxpayers file.

Invoicing and reporting supplies to a UIN holder

If you sell to an embassy or a UN agency, your obligations are ordinary, with one detail that decides whether your customer gets its money back.

• Charge GST as normal. Unless a specific exemption or notification covers the supply, you charge the applicable rate. The refund happens at the customer's end, not yours.
• Put the UIN on the tax invoice, in the field where you would put a customer's GSTIN, along with the customer's name. An invoice without the UIN is the most common reason a UIN holder cannot claim.
• Report it as B2B in GSTR-1, against the UIN. This is what makes the invoice appear in the holder's statement. A supply dumped into B2C never reaches it.
• Get the place of supply right. It determines whether you charge IGST or CGST plus SGST, and an error there becomes the customer's problem when the refund is examined.

A practical check before you raise the first invoice: search the number on the GST portal's taxpayer search, which accepts a GSTIN or a UIN, and confirm the name matches the body you are dealing with. For everyday customer checks with GSTINs, our free GST number search gives five lookups a day with no signup, and the API returns registration details and filing history in one call at ₹0.50 per verification. Both are built around the standard GSTIN format, so treat the portal as the place to confirm a UIN.

Engineering note: validating a UIN in your forms

Most GSTIN validators in the wild do two things: a regex that expects a PAN-shaped middle and a literal Z in position 14, and a check-character calculation. Both are correct for GSTINs, and both are the reason your form tells an embassy's accounts officer that their number is invalid.

The GSTIN regex post explains why position 14 is such a cheap, reliable check, and the checksum algorithm post explains the 15th character. Neither is designed for UINs, and you should not assume a UIN's last character satisfies the GSTIN checksum.

What works in practice:

1. Do not loosen your GSTIN regex. Dropping the Z or the PAN pattern to let UINs through also lets through thousands of mistyped GSTINs.
2. Add an explicit customer type. A "UN body / embassy (UIN)" option in the form, or an admin-only override, switches to a separate, looser check: 15 uppercase alphanumeric characters with a plausible state code.
3. Confirm UINs manually against the portal's taxpayer search before the first invoice, since the number cannot be checked structurally the way a GSTIN can.
4. Keep the error message honest. If a 15-character string fails only the Z or PAN check, say so, and point the user to the UIN option rather than calling the number invalid.

A minimal shape for the separate path:

// Pseudocode: route by customer type, not by guessing from the string
if (customerType === 'uin') {
    ok = /^[0-9]{2}[A-Z0-9]{13}$/.test(value);   // structure only; confirm on the portal
} else {
    ok = isValidGstin(value);                    // full regex + checksum
}

The full client-and-server pattern, including where each check belongs, is in GST number validation in forms. You can also paste a GSTIN into the GSTIN validator to see which structural rule a string fails.

Frequently asked questions