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UDIN: What It Is and How to Generate

UDIN (Unique Document Identification Number) authenticates documents certified by chartered accountants. Here is what it is and how to generate it.

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Accounting Standards & Bookkeeping
Published
August 20, 2026
Last updated
Oct 7, 2026
Reading time
4 min
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Last updated: October 2026Verified against: Government sources

UDIN (Unique Document Identification Number) authenticates documents certified by chartered accountants. Here is what it is and how to generate it.

What UDIN is

  • A unique number generated by CAs on the ICAI UDIN portal
  • Attached to certificates, audit reports and attestations
  • Lets anyone verify that a CA genuinely signed the document

How to generate

  • Log in to the ICAI UDIN portal
  • Enter the document details and figures
  • Generate and mention the UDIN on the document

Why it matters

UDIN curbs forged certificates and fake attestations in the name of CAs.

Frequently Asked Questions

What is UDIN?

A unique number CAs generate to authenticate the documents they certify.

How is UDIN generated?

On the ICAI UDIN portal by entering the document details.

Why was UDIN introduced?

To prevent forged certificates signed in the name of CAs.

Can UDIN be verified?

Yes — anyone can verify a UDIN on the ICAI portal.

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Quick recapKey facts & short answers

Key Facts About What It Is and

  • Applies in: All states across India, under the relevant central law.
  • Mode: Mostly online via the official government portal.
  • Typical timeline: Ranges from a few days to a few weeks depending on the case.
  • Non-compliance: May attract penalties, interest or late fees.
  • Expert help: TaxClue completes the entire process end to end for you.

What is UDIN?

A unique number CAs generate to authenticate the documents they certify.

How is UDIN generated?

On the ICAI UDIN portal by entering the document details.

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What It Is and: a key compliance topic in Indian tax and corporate law that businesses and individuals must understand to remain compliant.

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Why This Matters

Staying compliant with Indian regulations protects your business from penalties, interest and unnecessary legal trouble. It is always wise to maintain proper records and documentation so that any future scrutiny can be handled smoothly. Rules and thresholds in accounting standards bookkeeping are revised periodically, so it helps to review your obligations at the start of each financial year. Professional guidance from a qualified CA, CS or advocate ensures that filings are accurate and submitted well before the due date.

Small businesses and startups especially benefit from setting up a simple compliance calendar to track recurring deadlines. Government portals now allow most applications and filings to be completed online, reducing paperwork and turnaround time. Keeping your PAN, registration certificates and board resolutions organised makes every subsequent filing faster. When in doubt, it is better to seek clarification early rather than risk a notice or a late-filing penalty later.

A clear understanding of the applicable law helps you make confident, well-informed business decisions. TaxClue's experts regularly assist businesses across India with end-to-end accounting standards bookkeeping support at transparent, affordable pricing. Timely compliance also improves your credibility with banks, investors and government authorities. Reviewing your obligations with a professional at least once a year keeps your business audit-ready and stress-free.

Staying compliant with Indian regulations protects your business from penalties, interest and unnecessary legal trouble. It is always wise to maintain proper records and documentation so that any future scrutiny can be handled smoothly. Rules and thresholds in accounting standards bookkeeping are revised periodically, so it helps to review your obligations at the start of each financial year. Professional guidance from a qualified CA, CS or advocate ensures that filings are accurate and submitted well before the due date.

Small businesses and startups especially benefit from setting up a simple compliance calendar to track recurring deadlines. Government portals now allow most applications and filings to be completed online, reducing paperwork and turnaround time. Keeping your PAN, registration certificates and board resolutions organised makes every subsequent filing faster. When in doubt, it is better to seek clarification early rather than risk a notice or a late-filing penalty later.

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Disclaimer: This article is for general informational purposes only and does not constitute professional tax, legal or financial advice. Laws, rates and due dates change and can vary by individual case — always verify with the relevant government source (e.g. mca.gov.in, incometax.gov.in) or consult a qualified professional before acting. TaxClue accepts no liability for decisions taken based on this content.

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Questions, answered

Short, direct answers to the 4 questions readers ask most on this topic.

A unique number CAs generate to authenticate the documents they certify.

On the ICAI UDIN portal by entering the document details.

To prevent forged certificates signed in the name of CAs.

Yes — anyone can verify a UDIN on the ICAI portal.