GST INV-01 explained: e-invoicing and the IRN

Who must issue e-invoices

E-invoicing applies to notified registered persons, currently those whose aggregate turnover exceeded Rs. 5 crore in any preceding financial year from 2017-18. Once you cross the limit in any year, e-invoicing continues to apply even if turnover later falls.

• Covers tax invoices, credit notes and debit notes for B2B supplies, exports and supplies to SEZs
• Certain sectors are excluded, including SEZ units, insurers, banks and NBFCs, goods transport agencies, passenger transport services and multiplex cinema admissions
• B2C invoices are outside the IRN system

How the IRN works

You prepare the invoice in your billing system and upload its details in the INV-01 schema to the IRP. The IRP validates the data, generates the IRN, digitally signs the invoice and returns a signed QR code. The details then flow to GSTR-1 and can be used to generate Part A of the e-way bill. Under Rule 48(5), an invoice that should be e-invoiced but is issued without an IRN is not a valid invoice.

Time limits

• Taxpayers with aggregate turnover of Rs. 10 crore or more cannot report a document to the IRP more than 30 days after its date
• An IRN can be cancelled on the IRP within 24 hours of generation; after that, use a credit note
• Partial cancellation is not allowed; cancel the whole IRN and issue a fresh invoice with a new number

Common mistakes

Businesses often cross the Rs. 5 crore limit without noticing and keep issuing ordinary invoices, which can affect the buyer's ITC. Others report invoices late and hit the 30-day block. Monitor turnover each year, report on the day of issue, and reconcile IRP data with GSTR-1 and the Invoice Management System.

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This guide explains the law in general terms as of October 2026. Time limits and requirements can depend on the facts of your case and on the notice you received.