GST E-Invoicing in India: Meaning, Applicability, Generation Process

Key takeaways

• GST e-invoicing requires uploading invoice data to the Invoice Registration Portal (IRP) to obtain an Invoice Reference Number (IRN) before the invoice is legally valid under Rule 48(4).
• The current turnover threshold is ₹5 crore aggregate annual turnover, set by Notification No. 10/2023-Central Tax, effective 1 August 2023.
• Aggregate turnover is calculated PAN-wide, combining every GSTIN under the same PAN, across every financial year since 2017-18.
• Once turnover exceeds ₹5 crore in any year, e-invoicing applies permanently, even if turnover later falls; a first-time crossing takes effect from the next financial year.
• Exempted categories include SEZ units, government departments, banks and NBFCs, goods transport agencies, passenger transport operators, and multiplex cinema ticket issuers.
• Businesses with turnover of ₹10 crore or more face an additional 30-day limit for reporting each invoice to the IRP.
• An invoice without a valid IRN is not legally an invoice under Rule 48(5), risking the buyer's input tax credit and penalties under Section 122 of the CGST Act.

GST e-invoicing is a government-mandated system under Rule 48(4) of the Central Goods and Services Tax (CGST) Rules, 2017, that requires certain businesses to authenticate their invoices through a government portal before they are legally valid. Whether your company requires GST e-invoicing depends on whether your turnover has crossed the threshold that brings you into the system, and what changes operationally once it does.

The threshold is calculated across every financial year since GST began, not just the current one, and it applies permanently once triggered.

What GST e-invoicing means for a registered business

E-invoicing is the process of uploading specified invoice details to the Invoice Registration Portal (IRP), a government system, before that invoice is treated as valid under GST law. The IRP checks the data, generates a unique Invoice Reference Number (IRN), a 64-character code tied to that specific invoice, and returns a digitally signed QR code. Only after this round trip is the document a valid tax invoice.

This is different from simply creating an invoice in your billing software. A registered person covered by Rule 48(4) must prepare the invoice by including the particulars specified in FORM GST INV-01 (the prescribed e-invoice schema, covering supplier and buyer GSTINs, item-level HSN codes, and tax amounts, among other fields) and obtain the IRN before the invoice takes effect. Rule 48(6) confirms that once this route applies, the older triplicate or duplicate copy conventions for goods and services invoices no longer apply.

The ₹5 crore turnover threshold that triggers GST e-invoicing

E-invoicing currently applies to any registered business whose aggregate annual turnover exceeds ₹5 crore in any financial year from 2017-18 onwards, for B2B supplies and exports. This threshold was set by Notification No. 10/2023-Central Tax, which took effect on 1 August 2023 and reduced the earlier ₹10 crore limit.

Why the ₹5 crore e-invoicing threshold applies permanently once crossed

Once your aggregate turnover exceeds ₹5 crore in any single financial year since 2017-18, the e-invoicing requirement stays in force for every year afterward, even if your turnover later drops well below that figure. A company that had one unusually large revenue year (a large one-time contract, an asset sale, a bulk enterprise deal) doesn't get to exit the requirement once that year is behind it.

This design closes an obvious gap: without it, a business could structure invoicing or defer revenue recognition around the threshold year to avoid the system altogether, then resume normal invoicing once turnover has technically dropped. 

Businesses exempted from GST e-invoicing regardless of turnover

A small number of categories are exempted from e-invoicing regardless of turnover, under Notification No. 13/2020-Central Tax as subsequently amended. Most of these exemptions exist because the entity already issues a different document that serves as the tax invoice, or because the transaction is tracked through another regulatory channel.

• Special Economic Zone (SEZ) Units
•  Insurers
•  Banking companies or financial institutions, including a non-banking financial company (NBFC)
• Goods Transport Agency (GTA) supplying services in relation to transportation of goods by road in a goods carriage
• Suppliers of passenger transportation service
•  Suppliers of services by way of admission to exhibition of cinematograph films in multiplex screens
•  Persons registered in terms of Rule 14 of CGST Rules (OIDAR)

The step-by-step process for generating a GST e-invoice

1. Your billing or accounting software prepares the invoice as it normally would, including the fields required under FORM GST INV-01.
2. The invoice data is uploaded to the IRP, either directly or through a GST Suvidha Provider (GSP) that connects your software to the portal.
3. The IRP validates the data, checking for duplicate invoice numbers and verifying the GSTIN of both supplier and recipient.
4. The IRP generates the IRN, digitally signs the invoice data, and attaches a QR code containing the key invoice details.
5. The signed invoice, with IRN and QR code, is returned to your system and shared with the buyer.

The IRP does not create the invoice. It authenticates one that your own software has already prepared, which is why the software you use needs to support this upload step before the threshold applies to you.

The 30-day e-invoice reporting limit for businesses with ₹10 crore turnover and above

A separate rule restricts how long you can wait before reporting an e-invoice to the IRP. For taxpayers with aggregate annual turnover of ₹10 crore or more, an invoice, credit note, or debit note dated more than 30 days ago is rejected by the portal outright. This restriction, introduced by a GSTN advisory effective 1 April 2025, is distinct from the ₹5 crore applicability threshold covered above: it doesn't change who must e-invoice, only how quickly a covered business must report each document once issued.

Why an invoice without a valid IRN is not valid under GST

Rule 48(5) states plainly that an invoice issued by a person covered under Rule 48(4), in any manner other than the manner that rule specifies, is not treated as an invoice at all. It means an invoice that otherwise looks GST-compliant (correct tax rate, correct GSTIN, correct amount) still fails to qualify as a tax invoice if it's missing a valid IRN.

Since input tax credit (ITC) can only be claimed against a valid tax invoice, a buyer holding a document without a proper IRN risks having that ITC claim denied or delayed, through no fault of their own. On the seller's side, issuing invoices this way can attract penalties under Section 122 of the CGST Act, which covers incorrect invoicing among other contraventions.

The GST e-invoicing compliance checklist for startups nearing the ₹5 crore threshold

• Pull your turnover for every financial year since 2017-18, not just the current one, and sum it across every GSTIN registered under your PAN.
• If this financial year is the first time you've crossed ₹5 crore, note that the requirement applies from 1 April of the next financial year, not immediately; use that runway to prepare rather than treating it as urgent.
• Confirm whether your billing, accounting, or ERP software already supports IRP integration, either directly or through a GST Suvidha Provider, before the requirement takes effect.
• If your turnover is above ₹10 crore, build the 30-day reporting window into your invoicing calendar so month-end batches don't fall outside it.
• Flag any vendor invoices you receive that should carry an IRN but don't, since your own input tax credit is what's at risk, not just theirs.

FAQs on GST e-invoicing

1. Is e-invoicing mandatory for 1 crore turnover?

No. The current turnover threshold is ₹5 crore, set by Notification No. 10/2023-Central Tax effective 1 August 2023. A ₹1 crore threshold has been discussed at GST Council meetings as a possible future reduction, but no such change has been notified.