GST E-Invoicing in India (2026): Turnover Limit, 30-Day Rule & How to Stay Compliant

A shop crosses ₹5 crore in annual turnover and someone mentions "e-invoicing" for the first time. The invoice looks the same as always, the sale goes through, and three weeks later an accountant says the buyer can't claim input tax credit on it. Nothing about the transaction was wrong except one step: the invoice was never reported to the government's portal for a signed reference number.

E-invoicing under GST means generating an Invoice Reference Number (IRN) for eligible invoices through the government's Invoice Registration Portal (IRP) before the invoice is considered valid. This guide covers who must do it in 2026, the turnover limits that decide it, the 30-day reporting rule that was tightened last year, and what actually happens on the counter when a shop misses the window.

What is an e-invoice, exactly?

An e-invoice is not a new invoice format. It is your normal GST invoice, uploaded as a structured JSON file to the IRP, which validates it and returns two things: a 64-character Invoice Reference Number (IRN) and a signed QR code. Both get printed on the invoice you hand the customer. Without that IRN, a notified business's invoice is not a valid tax document under GST, no matter how correct the numbers on it are.

Who needs to e-invoice in 2026: the ₹5 crore line

E-invoicing is mandatory for any GST-registered business whose aggregate annual turnover (AATO) crossed ₹5 crore in any financial year from 2017-18 onward. This threshold has been in force since 1 August 2023 (Notification 10/2023-CT) and is unchanged through 2026. It covers B2B invoices, exports, and SEZ supplies. B2C retail sales are outside the scheme.

Two details catch businesses out every year:

• The test is PAN-wide, not per GSTIN. If you run two branches under the same PAN, their turnovers add together when checking against ₹5 crore, even if each branch individually sits below it.
• It is a one-way switch. The test looks at any financial year since 2017-18, not just the current one. Cross ₹5 crore once, even years ago, and e-invoicing applies going forward even if this year's turnover has since dropped below it.

If your turnover sits below ₹5 crore, none of this applies yet, but it is worth knowing where the line is before it moves. Our GST registration guide covers the earlier thresholds that decide whether you need a GSTIN at all.

The 30-day rule: a second, tighter deadline above ₹10 crore

A separate rule adds a hard deadline on top of the ₹5 crore mandate. From 1 April 2025, under a GSTN advisory dated 5 November 2024, any business with AATO of ₹10 crore or more must report each invoice, credit note, and debit note to the IRP within 30 days of the document date. Miss that window and the IRP simply rejects the request. There is no official way to reopen it afterward; the only option is to cancel the sale on your own books and reissue it as a fresh invoice.

The clock starts on the date printed on the invoice, not the date you get around to uploading it. An invoice dated 1 September has to reach the IRP by 30 September. This rule does not yet apply below ₹10 crore AATO, but the threshold has been lowered in stages before (₹100 crore in 2023, now ₹10 crore), so a business sitting just under it is one advisory away from being covered.

What happens if an invoice misses the window

Two separate costs stack on top of each other:

• The buyer loses input tax credit. An invoice without a valid IRN is not a valid GST document, so whatever your customer paid in GST on that purchase, they cannot claim it back. For a B2B buyer, that is real money, and it is the first thing that damages the relationship.
• The seller faces a penalty. Issuing an invoice without the required IRN falls under Section 122(1)(i) of the CGST Act: a penalty of ₹10,000 or 100% of the tax due on that invoice, whichever is higher.

Neither of these is a one-time inconvenience. Every late invoice resets the clock on both problems.

How IRN generation actually works

Underneath the portal, the process is the same four steps for every notified business:

1. Your billing system builds the invoice as a structured JSON payload in the government's NIC schema (currently version 1.1) — seller GSTIN, buyer details, line items with HSN codes and GST rates, and the tax split.
2. That payload is sent to the IRP, which validates the structure and the GSTIN checksums.
3. On success, the IRP returns a signed IRN and a QR code, which print on the customer-facing invoice.
4. If the invoice needs to be voided, it can be cancelled on the IRP within 24 hours of generation. After that window, cancellation is no longer possible, and the invoice has to be reversed with a credit note instead.

Building that JSON correctly by hand, for every invoice, every day, is where manual GST compliance usually breaks down. One wrong HSN code or a missing seller pincode is enough for the IRP to reject the whole payload.

How Astra Atlas handles this on the counter

Astra Atlas builds that NIC-schema payload automatically from data your shop is already recording: the GST rate and HSN code attached to each product, the CGST/SGST/IGST split calculated at the point of sale, and your business profile's GSTIN and address from Settings. A cashier never touches the raw JSON. During customer entry, the GSTIN lookup also flags whether a buyer's own GSTIN is e-invoice eligible, so you know before the sale closes whether this invoice is one that needs an IRN at all.

Every sale carries a visible IRN status in Sales History — generated, pending, cancelled, or not yet requested — so a shop crossing the ₹5 crore line for the first time can see exactly which invoices still need attention, rather than discovering a gap at month-end reconciliation. That status tracking matters as much as the generation step itself: the 30-day rule punishes invoices that get forgotten, not just invoices that get mishandled.

This is the same engineering pattern behind Astra Atlas's Loan Readiness score, where a GSTIN on file is worth 10 of the 100 points precisely because lenders check for it first. Compliance data you are already generating by billing through Atlas keeps paying off in places beyond the invoice itself.

A quick checklist before your next filing cycle

• Check your AATO against ₹5 crore across every financial year since 2017-18, not just this year's number.
• If you are at or above ₹10 crore, treat 30 days as the real deadline, not the invoice date — build in a buffer of a week or two for review.
• Confirm your billing software actually tracks HSN codes and the GST rate per product; see our GST calculation guide if you are still doing the CGST/SGST/IGST split by hand.
• If you are choosing billing software specifically for this, our comparison of GST billing software for small businesses covers what to look for beyond basic invoicing.

E-invoicing is not a separate task layered on top of billing. It is what billing becomes once your turnover crosses a line the government has already drawn. The shops that handle it cleanly are the ones whose invoice data was correct before the mandate applied to them, not the ones scrambling to fix HSN codes after the first rejected IRN.