IRN-Invoice Reference Number

  • Each Invoice uploaded by the tax payer will get the unique number called as Invoice Reference Number (IRN).
  • IRN is of 64 Characters length.
  • This IRN is unique number in the GST system, irrespective of tax payer, financial year and document type.
  • IRN is generated by the e-invoice system once the tax payer uploads the invoice details.
  • IRN can also be prepared by the tax payer and uploaded with the invoice details. The e-invoice system verifies this and accepts it accordingly.
  • IRN is generated using the computer algorithm (RSA256) based on the combination of the Supplier GSTIN, Document Type, Document Number and year of the Invoice (Financial Year).
  • IRN is hash of Supplier GSTIN + Fin. Year + Doc Type + Doc Number.
  • Financial Year is calculated based on the date of invoice. That is, the financial year starts with 1st April and ends on 31st March and represented as YYYY-YY. If the date is 03.01.2020, the financial year is 2019-20.
  • Document types are INV for Invoice, CRN for Credit Note, DBN for Debit Note.
  • Document Number is a number printed on the Document, being issued to the purchaser, and it is to be of maximum of 16 alphanumeric and / -.
  • The prefixing zeros, / - are ignored. However appearance of these characters in the middle and suffixing places are accepted as it is.
  • Using the above points, the tax payer can generate the IRN by self.
  • For example, tax payer with 01AAAAA9999A19N has issued the Invoice with Number ABC01234 on 12.12.2019 to his supplier, string used for hashing is

    01AAAAA9999A19N2019-20INVABC01234.

  • Removal of prefixing ‘o’,’-‘,’/’: If the invoice number is 01234 or /AB123 or -1234, then 1234 or AB123 or 1234 is used for hashing.
  • In case the invoice number is AB/123 or AB-123 or AB0123, then they are taken as it is.