Invoice Reference Number: Definition, Features, and How to Generate it?

Have you ever thought about how the Indian government maintains the uniqueness of the invoice? How is every invoice identified? How do Indian businesses maintain records of these invoices seamlessly?

That’s when the Invoice Reference Number (IRN) comes into play. IRN might look like a small 64-digit code, but it carries great importance for GST e-invoicing. It holds the digital identity for an invoice, driving a smooth, transparent, and compliant invoicing process.

Let’s scroll ahead to understand what is invoice reference number, the hash generation algorithm, and the steps to generate an IRN. Start reading right away. 

What is Invoice Reference Number? 

IRN full form is Invoice Reference Number, which is also called a hash and is created on the Invoice Registration Portal (IRP) through the hash algorithm.

Every invoice issued under the e-invoicing system must be registered with the Invoice Registration Portal, which assigns a unique ID and a QR code to the document.

Businesses with an annual turnover of ₹50Cr need to have the Invoice Reference Number to reduce tax evasion and comply with the GST standards.

The invoice's unique code prevents tampering of the receipts and ensures authenticity, since the code can’t be modified once generated. 

Latest Update- Apr 4, 2025

Effective from 1st June, 2025, the Invoice Registration Portal will consider invoice numbers to generate IRN. All the invoice numbers, irrespective of the format, will be converted to UPPERCASE characters, thus eliminating duplicate entries and ensuring uniqueness. 

What is the Hash Algorithm in the Invoice Reference Number? 

A hash algorithm refers to a hash creation functionality that translates a meaningful message, which can be a combination of letters, numbers, and special characters, into a code that makes it difficult to decrypt the original message.

​The Invoice Registration Portal (IRP) leverages this algorithm to generate an Invoice Reference Number as a part of the e-invoicing standard.

Characteristics of IRN

Created By: 

The Invoice Reference Number is created by the Invoice Registration Portal (IRP) and is administered under the GSTN portal. 

Components: 

IRN is made from the hash of the supplier’s GSTIN, document number, and financial year. 

Goal: 

To distinctly identify every invoice and avoid duplicacy. 

Why is it Needed? 

Every Business under the e-invoicing system needs to have the IRN code to ensure authenticity and transparency in the system. 

How to Generate an Invoice Reference Number? 

Invoice Generation

• The initial step is to generate the invoice using your accounting and billing software or an ERP system.  
• The invoice should have the invoicing number, supplier GSTIN, date of issuing, items purchased, and the corresponding GST rates.
• If you are looking for accounting and billing software to generate invoices, try Munim. It offers generating customized invoices, WhatsApp sharing, etc., in just a few clicks. 

Upload the Invoice to the IRP

• Once generated, upload the invoice receipt to the Invoice Registration Portal (IRP). 

Invoice Validation

• On the IRP, the invoice is not verified to see if it meets the GST rules.
• Entries like supplied GST identification number, duplicate invoices, date/ time of issuing, and other important details are cross-checked. 

Generate Invoice Reference Number

• Once the IRP is validated, the 64-character alphanumeric unique code generates a QR that includes all the crucial information. 
• Now, the GST system adds a unique signature to the IRN and QR code, which assigns integrity and authenticity. 

Send the Invoice to Supplier 

• Now, once the IRP adds a digital signature to the invoice, send the invoice to the supplier, which has an IRN and a QR code added to it.
• Now, the invoice can be used by the supplier, which then sends it to the recipient. 

Generate E-way Bill: 

• In case the bill includes shipment details, the invoice reference number auto-generates an e-way bill eliminating the need to manually generate it. 
• The system fetches all the details from the invoices and adds in the e-way bill. 

5 Common Mistakes to Avoid While Generating IRN

1. Missed a digit or added an incorrect GSTIN number.
2. Mismatched invoice data and JSON files uploaded.
3. Using duplicate invoice numbers.
4. Leaving mandatory fields like HSN codes, GSTIN number, etc., empty.
5. Generating Invoice Number Reference using low internet connectivity. 

What are the Norms to Cancel or Modify IRN? 

Invoice Reference Number can be cancelled or modified under certain circumstances as below:

• After generation, IRN can’t be modified but can be dismissed within 24 hours. If the 24-hour window is closed, it can be cancelled.
• In case the business detects a discrepancy in the invoice or the transaction gets aborted, the IRN needs to be cancelled asap using the IRP portal.
• For IRN cancellation beyond 24 hours, a debit credit note will be issued to amend the transactions.
• Please note, once the IRN is dismissed, the respective document number can’t be reused to generate another IRN. 

Application for Electronic Reference Number of an Invoice in International Trade 

• Import and Export businesses leverage IRN to ensure invoices comply with GST and customs norms, streamlining cross-border transport.
• For international trade, the invoice reference number facilitates real-time validation and auto-reporting, ensuring smooth duty transactions and customs clearance. This speeds up the movements of goods across the seas.
• It also encourages global trade efficacy, ensuring that all the compliance norms are met. 

Conclusion 

Though the invoice reference number looks small, it plays a crucial role in ensuring GST-compliant invoices. It integrates authenticity and transparency in the system, eliminating duplicate entries.

Hopefully, the blog has answered all your queries. Save the blog and stay tuned until we publish the next one. 

FAQs on Invoice Reference Number 

1. What is the purpose of IRN? 

The invoice reference number is used to add authenticity and transparency in the GST ecosystem. 

2. Who can issue an IRN? 

Businesses can generate invoice reference numbers against their invoices from the IRP. 

3. What is IRN full form? 

Full form of IRN is Invoice Reference Number. 

4. What are the common components of IRN? 

IRN is generated as a combination of the supplier’s GSTIN, invoice number, document type (invoice, debit, or credit), and financial year.  

5. How long will the government portal store the IRN? 

The government portal stores IRN for only 24-hours after it is generated. 

6. Should my e-invoice contain both invoice number and IRN? 

Yes, it is mandatory to have both invoice number and IRN on the e-invoice. 

7. Can I cancel the IRN once the e-way bill is generated? 

Once the e-way bill is generated and linked to IRN, it can’t be cancelled. 

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