GST E-Invoicing: When It Applies to Your Business (₹5 Cr) and How to Comply

GST e-invoicing becomes mandatory once your aggregate annual turnover crosses ₹5 crore (in any financial year from 2017-18 onward). From then on, every B2B invoice must be reported to the Invoice Registration Portal (IRP) to obtain an IRN and a QR code before it's issued — and an invoice raised without one is not a valid tax invoice, which can cost your customer their input tax credit. Here's what applies and how to comply.

Who e-invoicing applies to

E-invoicing is triggered by aggregate annual turnover (AATO) exceeding ₹5 crore — and the test looks at any financial year from 2017-18 onward, so once you cross it, you stay in. It applies to your B2B invoices, credit/debit notes, and exports — not to B2C invoices. Growing startups commonly cross this threshold and don't realise e-invoicing has switched on.

What changes in your billing

Instead of just raising an invoice from your accounting/billing tool, you must:

1. Report the invoice to the IRP (directly or through your GST software / ITC-integrated tool).
2. Receive back an IRN (Invoice Reference Number) and a signed QR code.
3. Issue the invoice with the IRN and QR code to your customer.

The IRP data also auto-populates parts of your GSTR-1 and the e-way bill system, so done right it reduces downstream work.

Why a non-compliant invoice is expensive

If you're required to e-invoice and you raise an invoice without an IRN, it is not treated as a valid invoice under GST. The practical consequences:

• Your customer may be denied input tax credit on it — which makes you a difficult supplier.
• You may face penalties for issuing an incorrect invoice.
• It creates reconciliation problems in your returns and a finding in any GST audit.

For a B2B startup, the customer-relationship cost (blocking their ITC) is often the sharpest.

The compliance trigger to watch

The thing to track is the turnover threshold crossing. E-invoicing switches on from the start of the financial year after you exceed ₹5 crore AATO — so you need to know when you crossed it and switch your billing before the new year starts. This is exactly the kind of threshold-triggered obligation that's easy to miss while you're focused on growth. (It sits alongside the rest of your GST compliance.)

Never miss the threshold switch

ComplianceStack tracks your turnover band and flags e-invoicing (and the other threshold-triggered GST obligations like GSTR-9C) when you cross ₹5 crore — so you switch your billing on time, not after a customer complains about a blocked credit. Get your free compliance health check.