An e-invoice can be cancelled on the Invoice Registration Portal only within 24 hours of IRN generation; after that window the IRN is permanent and the only reversal route is a credit note under Section 34 CGST Act 2017. The e-invoice JSON itself is not editable once the IRP has registered it — any change to a core field requires cancelling within the window, or a fresh invoice plus a credit note for the original. Cancellation reason codes are Duplicate, Data entry mistake, Order cancelled, and Others.
What the law actually requires
The 24-hour cancellation window is a system rule of the e-invoice framework, applied uniformly by the IRPs. Because the IRN is a deterministic hash of the document identity, it is permanently attached to the invoice once generated. There is no "amend IRN" function — the IRP deliberately does not allow editing a registered payload, because the hash would no longer match the original document and the integrity of the register would break.
This creates a sharp operational boundary for a private limited company:
Section 34 of the CGST Act governs credit and debit notes. A credit note is the statutory instrument for reducing the value of supply or tax in the supplier's books and reducing the recipient's ITC. Under s.34(1), a credit note must be issued for any of three events: (i) the taxable value or tax charged in the invoice is found to exceed the actual value or tax, (ii) the recipient has returned the goods, or (iii) the services are found to be deficient. If the reversal is simply "we issued the wrong invoice," the credit note route still works commercially — the wrong invoice is reversed and a correct invoice is issued in its place.
Worked example: Kolkata Apparels Pvt Ltd misses the window
Kolkata Apparels Pvt Ltd raises a B2B e-invoice for ₹8,00,000 plus ₹1,44,000 GST to a Mumbai buyer on 3 August. The next morning the sales team realises the buyer's GSTIN was keyed wrong — one digit off.
Now flip the timeline: the team discovers the error on 5 August — 42 hours after IRN generation. The cancellation window has closed. The correct sequence is now:
- Issue a credit note under s.34 for the original invoice, with its own IRN.
- Issue a fresh e-invoice with the correct GSTIN and a new document number.
- Report both in GSTR-1: the fresh credit/debit note in Table 9B (current-period notes); if the wrong invoice was already filed in a prior GSTR-1, correct the line via Table 9A (same-period amendments) or Table 13A (cross-return amendments) as applicable; the fresh invoice as a normal B2B line.
The cost of the late discovery is not a fine; it is an extra document, an extra IRN, and a GSTR-1 amendment cycle. If the buyer had already claimed ITC on the wrong-invoice version, they must reverse it in their GSTR-3B, and the supplier's credit note must be matched against that reversal.
What a director should actually watch
- Treat the 24-hour window as the real control. Build a same-day reconciliation of generated IRNs against the sales register. Any invoice flagged "wrong" must be cancelled before the next morning or the window closes.
- Cancel first, re-issue second — never re-issue on top of a live IRN. Two live IRNs for the same supply is a bigger reconciliation problem than one wrong invoice.
- Use the right reason code. Duplicate, Data entry mistake, Order cancelled, and Others are the four codes; the code is visible to the department, so use it truthfully.
- Track credit notes in the e-invoice system too. A credit note against an e-invoice must itself be reported to the IRP and get its own IRN — it is not a separate paper document.
- Amendments to GSTR-1 must follow. After any cancellation or credit note, the GSTR-1 for the relevant period must reflect the reversal. Auto-population does not silently fix a cancelled invoice retroactively.
What missing the window actually costs
The cost of missing the 24-hour window is rarely the invoice itself — it is the document chain that follows. A post-window reversal runs through a credit note with its own IRN, a fresh e-invoice with a new document number, and a GSTR-1 amendment entry. For a covered taxpayer, each of those documents consumes a unique document number in the financial year, and each must be reconciled against the e-invoice register and the buyer's GSTR-2B. The buyer, in turn, must reverse the ITC it may already have claimed on the wrong document, and match that reversal against your credit note.
There is also a penalty dimension. If the wrong invoice was issued to a registered person and the reversal is not matched in the returns, the system reads the gap as an unreported supply — primary exposure is a s.73 (non-fraud) or s.74 (fraud) demand for the tax plus interest and penalty, and separately s.122(1)(i) — ₹10,000 or the tax on the value of the supply, whichever is greater. The discipline that prevents all of this is a same-day IRN reconciliation: flag any wrong document within hours, cancel it inside the window, and re-issue before the month-end close.
FAQ
Can I cancel an e-invoice after 24 hours?
No. The IRP blocks cancellation after 24 hours from IRN generation. The IRN is permanent. Use a credit note under s.34 to reverse the supply instead.
Can I edit the invoice JSON after the IRN is generated?
No. Core fields are locked. There is no amendment function for a registered e-invoice. Change requires cancellation (within 24 hours) or a fresh invoice plus credit note.
What reason codes can I use for cancellation?
Four: Duplicate, Data entry mistake, Order cancelled, and Others. Pick the truthful one — the code stays on the record.
Do I need an IRN for a credit note?
Yes. A credit note against an e-invoice must itself be reported to the IRP and receives its own IRN before it is issued.
Does a cancelled e-invoice still show in GSTR-1?
The cancellation is reported to the IRP and flows into the GSTR-1 reconciliation. Ensure the corresponding document is excluded or reversed in the period's GSTR-1 so the register matches your books.
What if the buyer already claimed ITC on the wrong invoice?
They must reverse that ITC in their GSTR-3B, and your credit note must be reflected so the reversal matches. A late credit note that arrives after the buyer's s.16(4) ITC deadline can strand the credit entirely.
Use the e-invoice applicability checker to confirm which of your invoices carry the IRN obligation: /tools/e-invoice-applicability-checker. For a GST compliance audit of your company, visit pvtltd.co.
Sources
- Section 34 CGST Act 2017 (credit and debit notes)
- Section 16(4) CGST Act 2017 (time limit for ITC)
- IRP cancellation rules — 24-hour window and reason codes (e-invoice portal / IRP documentation)
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