E-invoicing in India — the ₹5 crore threshold guide for SMEs

Who must e-invoice — the ₹5 crore rule

Answer first: e-invoicing is mandatory for every GST-registered business whose aggregate annual turnover (AATO) crossed ₹5 crore in any financial year from 2017-18 onwards. That threshold has been in force since 1 August 2023, and once you cross it in any year, the mandate applies from the start of the next financial year — permanently, even if turnover later falls. It covers B2B tax invoices, exports, and the credit and debit notes issued to registered buyers. B2C invoices are outside the mandate.

Note the word aggregate: AATO is computed PAN-wide, across all GSTINs and all branches, and it includes exempt supplies and exports. A trader with ₹3 crore in one state and ₹2.5 crore in another is over the line. If you are anywhere near ₹5 crore on any reading, treat yourself as in scope and confirm the details with your CA — the thresholds and exemptions in this guide are current as of July 2026, and they change by notification.

How the threshold fell — ₹500 crore to ₹5 crore

E-invoicing arrived for giants and marched steadily down to SMEs. The history matters because it tells you where this is going: the direction has only ever been downward, and businesses below ₹5 crore should expect the net to widen rather than shrink.

Each step brought hundreds of thousands of additional taxpayers into the system. The practical lesson from every wave has been the same: the businesses that struggled were not the ones lacking an internet connection — they were the ones whose invoice data was incomplete. Missing HSN codes, unverified buyer GSTINs and ad-hoc invoice formats are what the IRP rejects. Getting the underlying billing discipline right — the subject of our GST invoice compliance checklist — is 90% of e-invoice readiness.

How IRN, IRP and the QR code work

The flow has three actors: your billing software, an Invoice Registration Portal (IRP) — the NIC portal plus the private IRPs empanelled since 2023 — and the GST system behind it.

• Your system prepares the invoice data in the notified e-invoice schema (INV-01): supplier and buyer GSTINs, invoice number and date, line items with HSN, taxable values, the CGST/SGST/IGST split, and totals.
• The IRP validates and registers it — checking GSTINs, duplicate detection and schema completeness — then generates the IRN, a unique 64-character hash computed from your GSTIN, the document number and the financial year.
• The IRP signs the invoice and returns a QR code embedding both GSTINs, invoice number, date and value, main HSN, line count and the IRN. The IRN and QR must appear on the invoice copy the buyer receives — that is what makes it a legally valid e-invoice.
• The details flow onward automatically — into your GSTR-1 (auto-population) and, where goods move, into the e-way bill, which for mandated taxpayers rides the same IRN. That is why e-invoicing done right makes GSTR reconciliation easier, not harder.

One misconception is worth killing: the government does not design your invoice. Your printed or emailed invoice looks the way it always did — with the IRN and QR added. The schema governs the data you report, not the paper you present.

What is covered — and what is exempt

In scope for a mandated business: B2B invoices to registered persons, exports (with or without payment of tax), and credit and debit notes against B2B supplies. Out of scope: B2C invoices, bills of supply, delivery challans and self-invoices for reverse charge purchases from unregistered suppliers.

Certain supplier categories are exempt from e-invoicing regardless of turnover — notably banks and NBFCs, insurers, goods transport agencies, passenger transport operators, multiplex cinema admissions, and SEZ units (SEZ developers, by contrast, are covered). Government departments and local authorities are also outside. If you supply to a SEZ or an exempt entity, you still e-invoice — the exemption belongs to the supplier category, not the buyer. Two practical corollaries for SMEs: a B2C-heavy retailer may cross ₹5 crore and still e-invoice only its small B2B slice; and the separate dynamic QR code requirement on B2C invoices applies only to businesses above ₹500 crore — do not confuse the two.

Reporting windows, cancellation and penalties

The 30-day reporting window

Taxpayers with AATO of ₹10 crore and above must report invoices to the IRP within 30 days of the invoice date. The window first applied to ₹100 crore-plus businesses from November 2023 and was extended to ₹10 crore-plus from 1 April 2025; beyond it, the IRP simply rejects the document. Businesses between ₹5 and ₹10 crore currently have no hard window, but same-day reporting is the only sensible practice — an invoice without an IRN is not yet an invoice.

Cancellation is a 24-hour door

An e-invoice can be cancelled on the IRP only within 24 hours of generation, and only in full — there is no partial cancellation and no amendment on the IRP. After 24 hours, corrections travel the normal GST route: a credit or debit note, reflected in your returns. This is exactly where linked billing documents earn their keep — a credit note tied to its invoice keeps the ledger, the returns and the IRP record telling one story.

What non-compliance costs

An invoice that should carry an IRN but does not is treated as not issued. Penalties commonly cited are up to ₹10,000 per invoice for non-generation and ₹25,000 for an incorrect e-invoice, and the commercial damage is often worse: your buyer's input tax credit is jeopardised because the invoice never reaches their GSTR-2B, and buyers increasingly refuse to pay against non-IRN invoices. Exact exposure depends on facts — take your CA's advice rather than this page's word for it.

What changes in your billing process

Surprisingly little — if your billing was disciplined to begin with. The sequence dispatch → tax invoice → payment → books described in the pillar guide stays intact; e-invoicing inserts one step between raising the invoice and handing it over: report to the IRP, receive the IRN and QR, print them on the invoice. What it punishes is looseness that manual billing tolerated for years:

• Invoice numbers must be clean — unique within the financial year, no duplicated or recycled series, because the IRN is computed from the number itself.
• Every item needs its HSN and rate — a blank or wrong HSN is a rejection at the portal, not a shrug at the counter.
• Buyer GSTINs must be real and current — cancelled or mistyped GSTINs fail validation; verify at onboarding, not at invoice time.
• Corrections become formal — after the 24-hour window, only credit and debit notes fix an invoice, so casual edit-and-reprint habits must end.

The SME preparation checklist

If you are approaching ₹5 crore — or already past it — this is the order of work:

• 1. Check AATO properly — PAN-wide, every financial year since 2017-18, including exempt supplies and exports. Crossing once is crossing forever.
• 2. Clean the masters — map every item to its HSN and GST rate (bulk import beats hand-editing), and verify every B2B buyer's GSTIN.
• 3. Confirm your software produces complete e-invoice data — full schema fields, IRN and QR printed on the invoice, cancellation handled inside the 24-hour window.
• 4. Rehearse before the deadline — run a pilot month where every B2B invoice goes through the flow, so the first mandated invoice is not the first attempt.
• 5. Brief the people — billing staff on the no-edit rule and the credit-note path, dispatch staff on the e-way bill linkage, and your CA on the go-live date.

How Fast Billing Software keeps you e-invoice-ready

Fast Billing Software approaches e-invoicing the way the IRP does: as a data problem. Every tax invoice is raised against a real dispatch or order with the buyer's GSTIN, item-wise HSN from the bulk item↔HSN↔GST map, the automatic CGST/SGST/IGST split and amount in words — the complete, structured data an e-invoice needs, with QR support on the invoice. The GST, e-Way Bill & e-Invoice integration covers the compliance surface; the same confirmed invoice then posts to Tally as a sales voucher through the Tally integration, so IRP, returns and books stay in one line. Corrections follow the compliant path by design — an auto credit note against the original invoice, never an edited copy. Pricing is straightforward and per-deployment, with no per-invoice fees that punish growing volume.

Frequently asked questions