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Invoice Reference Number

Invoice Reference Number

Invoice Reference Number

Invoice Reference Number (shortly and more popularly known as IRN) is a unique number generated for each invoice uploaded on an e-invoice system. The number is also known as ‘hash’. The number is generated using a hash generation algorithm.

The present article explains the format of IRN; generation of IRN; modes of generation of IRN; cancellation of IRN and synopsis thereon.

Format of Invoice Reference Number

Each invoice uploaded on the e-invoice portal by the supplier will be allotted a unique number known as ‘Invoice Reference Number’. IRN is a 64 characters long number. The combination of 64 characters long IRN is tabulated hereunder-

Format of IRN Description

Supplier GSTIN

(i.e., Goods and Services Tax Identification Number)

The 15-digit number allotted while obtaining registration under GST.
Financial Year The respective financial year in which the invoice is generated in format YYYY-YY. For example, for the financial year 2021-2022. The format will be taken up as 2021-22.
Document Type

Invoice, debit note or credit note. The format will be as under-

INV – Invoice

DBN – Debit Note

CBN – Credit Note

Document Number It is a number printed on the respective document.

Generation of Invoice Reference Number

In order to generate IRN for each invoice, the supplier needs to follow the below narrated steps-

STEP 1 – Generation of normal invoice via ERP/ accounting software-

Firstly, the supplier is required to generate the invoice in a normal way using its own ERP or accounting software. Here, it is important that the supplier needs to update its ERP/ accounting software in order to include the following mandatory fields in the invoice-

  • Document Type Code;
  • Supplier’s details-
    • Legal Name;
    • GSTIN;
    • Address;
    • Place;
    • State Code;
    • Pin Code;
  • Document number;
  • Preceding invoice reference and date;
  • Document date;
  • Recipient’s details-
    • Legal name;
    • GSTIN;
    • Address;
    • State Code;
    • Place of supply – state code;
    • Pin Code;
  • Invoice Reference Number;
  • Shipping To details-
    • GSTIN;
    • State Code;
    • Pin Code;
  • Dispatch from details-
    • Name;
    • Address;
    • Place;
    • Pin Code.
  • Supply type code;
  • Item description;
  • HSN code;
  • Item price;
  • Assessable value;
  • Rate of GST;
  • Value of IGST;
  • Value of CGST;
  • Value of SGST;
  • Total invoice value.

STEP 2 – Creation of JSON file and uploading of the same on IRP-

The ERP/ accounting software should be capable of generating JSON (i.e. JavaScript Object Notation) of the normal invoice generated as per STEP 1 above. Post generation of JSON, the said JSON file is to be uploaded on Invoice Registration Portal (IRP).

STEP 3 – Generation of IRN-

Hash will be generated based on the JSON file uploaded by the supplier on IRP. The hash so generated will become a unique Invoice Reference Number (IRN) individually for each invoice so uploaded on IRP.

Modes of the generation of Invoice Reference Number

The registered person can adopt any of the following modes for the generation of IRN-

  1. Offline mode,
  2. Direct API integration, and
  3. API integration through GSP.

Cancellation of Invoice Reference Number

Invoice Reference Number generated via e-invoice portal can be cancelled within 24 hours. Once the Invoice Reference Number relating to an e-invoice is cancelled, then another Invoice Reference Number cannot be generated for the same invoice number.

Notably, partial cancellation of e-invoice is not possible. Further, cancellation of IRN is not possible in case the valid e-way bill exists for the respective IRN.


  • Generation of IRN-
    • The supplier will generate an invoice using its usual ERP/ accounting software.
    • The supplier will upload the invoice details using JSON format into the Invoice Reference Portal (IRP).
    • IRP will generate the hash.
    • Hash so generated will become the Invoice Reference Number of the respective e-invoice.
    • On confirmation of uniqueness, IRP will send back the digitally signed JSON with IRN and QR code to the supplier.
  • Cancellation of IRN-
    • Cancellation of IRN is possible only within 24 hours of its generation.