How to Generate UDIN: Step-by-Step Guide for CAs (2026)

To generate a UDIN, log in at udin.icai.org, pick the document type, enter client details and key figures, confirm with an OTP and note the 18-digit number.

Once you've done it a few times it takes a couple of minutes per document. Where firms actually get into trouble isn't the portal. It's everything around it: UDINs generated weeks late, figures that don't match the final signed copy, or nobody being sure whether that net worth certificate from March ever got one.

Here's the full process, the rules that matter, and a simple way to keep track of UDINs across the firm.

What a UDIN is, and when you need one

UDIN stands for Unique Document Identification Number. It's an 18-digit number generated on ICAI's portal for every document a practising Chartered Accountant certifies or attests, so that banks, regulators and anyone else relying on the document can confirm it really came from that member.

The format tells you something. The first two digits are the year, the next six are your membership number, and the last ten are generated by the system. A UDIN starting with "26" followed by your membership number was generated in 2026.

It was made mandatory in three phases in 2019:

• All certificates, from 1 February 2019
• GST and income-tax audit reports, from 1 April 2019
• All other audit and assurance work, from 1 July 2019

So the working rule today is simple: if you sign it as a practising CA, assume it needs a UDIN. The facility is available to members holding a full-time Certificate of Practice.

First-time registration on the UDIN portal

1. Go to udin.icai.org and choose the option to register as a first-time user.
2. Enter your membership number along with the details ICAI uses to confirm it's you (your date of birth and date of enrolment).
3. Enter the OTP sent to your registered mobile number and email.
4. Your login credentials arrive by email. Log in and set your password.

One thing worth checking first: the OTPs go to the mobile number and email registered with ICAI. If yours are out of date, update them on ICAI's Self Service Portal before you start, or you'll be stuck at step 3.

How to generate a UDIN, step by step

1. Log in and choose Generate UDIN.
2. Pick the type of document. Certificate, GST or tax audit report, other audit and assurance work, or other documents. Take a second over this, because it decides which fields come next.
3. Enter the client details the portal asks for, such as the client's name and identifier.
4. Enter the date of signing. This is the date the 60-day window runs from, so get it right.
5. Enter the key figures from the document. For a certificate, the amounts you're certifying. For an audit report, the headline numbers from the financial statements. These must match the signed copy exactly.
6. Add a document description. The portal wants at least 15 characters. "Net worth certificate for visa, Mr R. Nair" works. "Certificate" doesn't.
7. Confirm with the OTP. The UDIN appears on screen and is emailed to you.
8. Put the UDIN on the document, near your signature, along with the date and place.

The 60-day rule, and why same-day is better

ICAI allows a UDIN to be generated within 60 days of the date the document is signed. It used to be 15 days until ICAI aligned it to 60.

ICAI has occasionally allowed one-off relaxations. In April 2026, for example, it opened a window to generate UDINs missed on documents signed between 22 October and 22 November 2025. Those are exceptions, though, not something to plan around.

In practice, generate the UDIN the same day you sign. A certificate without one can be turned away by the bank or authority receiving it, and "we'll do it later" is exactly how a stack of them drifts past 60 days during a busy month.

Tax audit reports on the income-tax portal

If a tax audit report (Form 3CA/3CB with 3CD) was uploaded on the e-filing portal before the UDIN was generated, the portal has an Update UDIN option that lets the CA add it afterwards. Don't leave this open. An uploaded report without a UDIN against it is an easy item to forget in September, and a hard one to explain later.

Revoking a UDIN

If you generated a UDIN with the wrong details, you can revoke it on the portal, give a reason, and generate a fresh one. Revocations are recorded against your membership, so treat it as a way to correct genuine mistakes, not an undo button for careless entries.

How others verify a UDIN

Anyone can check a UDIN on the same portal through the Verify UDIN option. They enter the UDIN and a few details about themselves, confirm with an OTP, and see the member and document details. Banks and government departments do this routinely. It's the main reason the figures you enter need to match the document exactly.

Common mistakes

• The draft changed after the UDIN was generated. The client asked for one more revision, the figures moved, and the UDIN still carries the old numbers. Generate it on the final, signed version only.
• Wrong document type. A tax audit report generated as a certificate, or the other way round.
• A typo in the signing date. It affects the 60-day calculation and makes the record look wrong on verification.
• The partner's phone as a bottleneck. Staff prepare the documents, but every OTP goes to the signing partner. In the last week of September that's a lot of interruptions. Batching UDIN generation once or twice a day works better than doing it one at a time.
• No internal record. The portal lists what you've generated, but it has no idea which client file, engagement or invoice each UDIN belongs to.

Keep your own UDIN register

A simple internal register fixes most of the problems above. For each document, record the date of signing, client, document type, key figures, the UDIN, who prepared it and whether it has been billed.

That last column pays for itself. Certificates are small, quick jobs, and they're the easiest work in a CA office to forget to invoice.

If you'd rather not maintain it by hand, QwikCA includes a UDIN register tied to the client record, so the UDIN, the document and the invoice sit together. A partner can pull up every certificate signed for a client in a few seconds, which also helps when a bank calls to confirm one.

FAQs

How many digits are there in a UDIN?

Eighteen: two for the year, six for the membership number and ten generated by the system.

What is the time limit to generate a UDIN?

60 days from the date of signing the document. Generating it on the day you sign is the safer habit.

Can one partner generate a UDIN for a document another partner signed?

No. The UDIN is generated by the member who signs the document, from their own login, and it carries their membership number.

Can a UDIN be cancelled?

It can be revoked on the portal with a reason, and a new one generated. Revocations are recorded, so use it only for genuine errors.

How do I check whether a UDIN is genuine?

Use Verify UDIN on udin.icai.org. You'll need to enter the UDIN and your own details, and confirm with an OTP.

ICAI updates UDIN guidelines from time to time. Check the latest announcements on udin.icai.org before relying on a time limit.