GST e-Invoice ≥ ₹5 Cr — the 14-day setup checklist

Who is in scope

From 1-August-2023, the e-invoicing threshold dropped to ₹5 Cr aggregate turnover. "Aggregate turnover" is computed across all GSTINs of the same PAN, on an all-India basis, including exempt, zero-rated, taxable, and non-GST supplies. Once your turnover crossed ₹5 Cr in any FY from FY 2017-18 onwards, you are in — even retrospectively.

Excluded categories — these PAN-level entities are exempt from e-invoicing even above ₹5 Cr:

• SEZ units (SEZ developers are NOT exempt).
• Insurance companies.
• Banking, NBFCs, financial institutions.
• GTA (transport of goods by road).
• Passenger transport service providers.
• Cinema multiplex services.
• OIDAR service providers.
• Government departments (CGST + SGST).

What documents need IRN

Document	e-Invoice (IRN) required?
B2B tax invoice	Yes
B2G (govt) tax invoice — sale to govt undertakings or PSUs that are registered persons	Yes
Export tax invoice (with or without payment of tax)	Yes
Credit note / debit note (to a registered recipient)	Yes
B2C invoice (to unregistered customer)	No (but dynamic QR mandatory if turnover > ₹500 Cr)
Bill of supply (exempt / composition)	No
Self-invoice for reverse-charge supply from unregistered supplier	No
Delivery challan, advance payment receipt, refund voucher	No

The 30-day reporting cliff

From 1-November-2023 (turnover ₹100 crore+) and 1-April-2025 (turnover ₹10 crore+), GSTN enforces a 30-day cliff: an invoice can only be reported to the IRP within 30 days of the invoice date. Day 31, the IRP rejects. The invoice can no longer get an IRN, which means:

• The supplier cannot legally claim it as a tax invoice (Rule 48(4)).
• The recipient cannot claim ITC under Sec 16 against an invoice without IRN where IRN was mandatory.
• The supplier remains liable for output tax, but ITC is lost — a pure cost.

Currently this 30-day rule applies to GSTINs with AATO ≥ ₹10 Cr. The rule will likely expand to all e-invoice-eligible GSTINs in future tranches. Treat 30 days as a hard line in your ERP today.

The 14-day setup plan

Days 1-2: Register on IRP

1. Identify your primary IRP — NIC IRP-1 is the default at einvoice1.gst.gov.in. Alternatives include IRP-2 through IRP-6 for redundancy.
2. Register your GSTIN on the IRP with your authorised signatory.
3. Generate API credentials (client ID, secret) for ERP integration.

Days 3-7: Validate ERP / accounting software

1. Confirm software vendor (Tally Prime, Zoho Books, Busy, custom ERP) has an active e-invoice plug-in.
2. Test in sandbox with 5-10 invoices of different types: regular B2B, B2B reverse charge, export with LUT, credit note, debit note.
3. Verify IRN and QR code embed correctly in PDF.
4. Validate the IRN appears in GSTR-1 (auto-flow) and in GSTR-2B for the recipient.

Days 8-10: Master data clean-up

1. Audit customer master for GSTIN format (15 chars; check sum), state code consistency, and "registered / unregistered" flag.
2. Map every HSN to a 6-digit HSN where AATO ≥ ₹5 Cr (4-digit HSN if AATO < ₹5 Cr).
3. Ensure place of supply rules are codified per item (intra-state vs inter-state, SEZ flag, export flag).
4. Set up reverse-charge supplier flag and self-invoice template.

Days 11-13: Process controls

1. Block invoice PDF generation until IRN is fetched — i.e. no PDF without IRN.
2. Build a daily exception report: invoices without IRN, IRN-fetch failures, IRN cancelled within 24-hours.
3. Document the 24-hour cancellation rule — IRN can be cancelled (full, not partial) only within 24 hours of generation; after that, you issue a credit note + debit note.

Day 14: Reconciliation handshake

1. Pull your e-invoice register from IRP for the past month.
2. Reconcile against GSTR-1 auto-populated rows. They should match.
3. Reconcile cancelled IRNs with credit notes issued.
4. Sign off the e-invoice SOP and circulate to AR / billing / finance.

Common failure modes we've seen

1. Software generates invoice PDF without fetching IRN. Tally Prime, for instance, will print without IRN if connection to IRP fails — operator must explicitly retry. Add a hard block.
2. Wrong place of supply on inter-state sale. If the recipient state is set to your own state, GSTR-1 books it as intra-state but the IRP may have validated it as inter-state. Reconciliation breaks.
3. Branch transfers within same PAN. If two GSTINs belong to the same PAN (Tamil Nadu + Karnataka), supply between them is a "supply" for GST. e-Invoice is required if either GSTIN crossed the threshold. People miss this.
4. Reverse-charge self-invoice generated with IRN. Wrong — self-invoice for RCM supply from unregistered supplier does NOT need IRN. Some software does this anyway and corrupts the master.
5. E-way bill not auto-generated. Once IRN is fetched, e-way bill (Part A) is auto-prepared on the e-way portal. Part B (vehicle number) still needs manual entry by the consignor / transporter. Confirm that auto-Part-A is enabled.
6. Cancel-and-reissue mistake. If you spotted a quantity error 30 hours after IRN — you cannot cancel. You must issue a credit note for the error and a fresh invoice for the correct quantity. Cancelling now is locked.

What if you're late starting?

If you crossed ₹5 Cr in an earlier FY but never set up e-invoicing, the position depends on how much invoicing is at stake. For the period of non-compliance:

• Invoices issued without IRN where IRN was required are NOT valid tax invoices under Rule 48(4).
• Recipient ITC is at risk — you may face refund-back claims from customers.
• Sec 122 penalty: ₹10,000 or the amount of tax evaded, whichever is higher.
• For ongoing periods within 30-day window: generate IRN now; for past invoices outside 30-day window: nothing you can do at IRP — document the gap, brief auditor, accept the Sec 122 risk.

Going forward, file a CGST Sec 74 declaration (voluntary disclosure) with the jurisdictional officer if the gap is material. Often we can negotiate a no-penalty closure if voluntary disclosure precedes any scrutiny notice.

Bottom line

e-Invoice is not a compliance you can half-implement. The 30-day cliff is a one-shot — miss the window and the invoice loses validity, with the recipient losing ITC and the supplier holding the bag. Spend the 14 days of setup once; document the SOP; instrument the exception report. Done right, e-invoice becomes invisible. Done wrong, every invoice is a potential ₹10,000 penalty plus customer credit loss.

Related

• e-Invoice eligibility & setup tracker
• GSTR-1 vs IRP reconciliation
• GST notice response — 7-step playbook
• GST liability calculator