GST E-Invoicing Explained: What Vadodara MSMEs Must Know

What is a GST e-invoice, in plain words?

An e-invoice is not a PDF you email. It is your normal tax invoice, created in your billing or accounting software, whose details are sent in a standard format to a government-authorised Invoice Registration Portal (IRP) before you issue it. The IRP checks it, gives it a unique Invoice Reference Number (IRN), signs it digitally and returns a QR code.^[6] You then print or send the invoice with that IRN and QR code on it.

The point for the government is that every B2B invoice is recorded at the moment it is issued. The point for you is that the same data can flow into your GSTR-1 return and, where needed, into an e-way bill, instead of being typed again.

E-invoicing covers supplies to GST-registered buyers (B2B), exports, and the credit and debit notes linked to them. Sales to ordinary consumers (B2C) are not reported to the IRP under this rule.^[2]

Who has to issue e-invoices in 2026?

The rule sits in rule 48(4) of the CGST Rules and the notifications made under it. The current limit was set by Notification 10/2023-Central Tax, dated 10 May 2023, which replaced “ten crore rupees” with “five crore rupees” from 1 August 2023.^[1] As of October 2026, no later notification has changed that figure.^[7]

Two words in the underlying notification do most of the work:

• “Any preceding financial year from 2017-18 onwards.” You are covered if your aggregate turnover exceeded ₹5 crore in any financial year since 2017-18, not just last year.^[2] One strong year is enough, and a weaker year after it does not take you out.
• “Aggregate turnover.” The CGST Act defines this as the value of all taxable and exempt supplies, exports and inter-State supplies of persons having the same PAN, computed on an all-India basis, excluding the GST itself.^[3] Inward supplies on which you pay reverse charge are excluded.

Some classes are exempt even above the limit, including SEZ units, insurers, banks and other financial institutions including NBFCs, goods transport agencies, passenger transport services, cinema admission services, and government departments and local authorities.^[7] If you are one of these, confirm the exact wording with your CA.

How does the ₹5 crore test work if you have more than one GSTIN?

This is where many growing MSMEs get caught. GST registration is per state, and some businesses also take separate registrations for different units. E-invoicing does not care how many GSTINs you have. It looks at the turnover of everything under the same PAN.^[3]

Use the decision steps below to check where you stand:

1. List every GSTIN registered under your PAN, in every state.
2. For each financial year from 2017-18 to the last completed year, add up their aggregate turnover.
3. If any single year’s total is above ₹5 crore, you are covered for B2B invoices, exports and related notes, unless you fall in an exempt class.
4. If any year’s total is ₹10 crore or more, the 30-day reporting limit described below also applies to you.^[4]
5. If no year crossed ₹5 crore, you are not required to e-invoice. Keep checking every April.

What are the two deadlines that catch businesses out?

E-invoicing has two clocks. Neither is about filing returns. Both are about the invoice itself.

The 24-hour cancellation window

Once an IRN is generated, the invoice can be cancelled on the IRP only within 24 hours, and only in full. You cannot cancel half an invoice. If an e-way bill is active against it, that has to be cancelled first. After cancellation, the same invoice number cannot be used again to get a new IRN.^[8] After 24 hours, a mistake is corrected through a credit note or debit note, which is itself e-invoiced.^[8]

The 30-day reporting limit

From 1 April 2025, taxpayers with an aggregate annual turnover (AATO) of ₹10 crore or more cannot report an e-invoice to the IRP if it is more than 30 days old. GSTN’s own example: an invoice dated 1 April 2025 cannot be reported after 30 April 2025. The block applies to invoices, credit notes and debit notes. GSTN said there is no such restriction below ₹10 crore “as of now”.^[4]

The 30-day block is checked on aggregate annual turnover as GSTN computes it, which may not be the same as your “highest year” test. If you are near ₹10 crore, ask your CA which figure the portal shows for you.

Why should an MSME below ₹5 crore care about e-invoicing?

Because you are probably a buyer from someone who is covered. Rule 48(5) of the CGST Rules says that an invoice issued by a person who must e-invoice, in any other manner, “shall not be treated as an invoice”.^[5] Your input tax credit depends on holding a valid tax invoice. So if a covered supplier sends you a plain invoice without an IRN, the GST you paid on it is exposed.^[7]

In practice this means a small unit buying steel, chemicals or packaging from a larger distributor should check one thing on every purchase invoice: is there an IRN and a QR code? If not, and the supplier is large enough to be covered, ask for a proper e-invoice before you book the credit. A ten-second look at incoming bills is cheaper than reversing credit later.

The reverse also happens. Large buyers often ask their smaller suppliers whether they are covered. If you have crossed ₹5 crore across all your GSTINs and haven’t started, your customers’ accounts teams may notice before you do.

How do you actually generate an e-invoice?

There are three common routes, and the choice depends mostly on how many invoices you raise.

• Through your accounting or billing software. Most GST billing software can send invoice data to an IRP directly and print the IRN and QR code. This is the usual route if you raise more than a handful of B2B invoices a day.
• On the e-invoice portal itself. Registered taxpayers can log in to the government e-invoice system and generate IRNs, and the portal also handles cancellations within the 24-hour window.^[6]
• With NIC’s offline tool for very small volumes. GePP is an Excel-based tool from NIC for small taxpayers. It is set up per GSTIN and handles only up to ten pending invoices at a time, and it does not validate GSTINs or HSN codes, so errors are on you.^[9]

Whatever the route, the item master matters. Covered taxpayers must use 6-digit HSN codes on outward supplies.^[6] Clean customer GSTINs, item codes and units before you switch on e-invoicing. Most rejections at the IRP come from bad master data, not from the software.

If you already use a SaaS billing tool, check whether e-invoicing is included or charged extra, and who owns the data. Our explainer on what SaaS means for a Vadodara business covers what to ask before you sign.

What are the common e-invoicing mistakes to avoid?

• Checking only one GSTIN’s turnover. The test is PAN-wide and all-India.^[3]
• Checking only last year. Any year from 2017-18 counts.^[2]
• Issuing the invoice first, reporting later. The IRN should be on the invoice you give the customer. If you are at ₹10 crore AATO or more, “later” has a hard 30-day limit.^[4]
• Trying to fix an IRN after a day. After 24 hours you need a credit or debit note, not a cancellation.^[8]
• Not checking purchase invoices. Your credit depends on your covered suppliers doing it right.^[5]
• Running two systems. If sales and stores live in one tool and invoices in another, numbering and HSN mismatches creep in. Our guide to accounting software vs ERP vs custom finance tools explains how to decide where invoicing should live, and our scorecard on whether a small GIDC unit really needs an ERP helps if you are weighing a bigger step.

Frequently asked questions

Sources and further reading

1. CBIC / GST Council. Notification No. 10/2023-Central Tax, 10 May 2023. Sets the ₹5 crore limit from 1 August 2023. Gazette copy: egazette.gov.in.
2. GST Council. Notification 10/2023-Central Tax: summary and amendment history. Amends Notification 13/2020-CT, whose first paragraph (as amended by 70/2020-CT) uses “any preceding financial year from 2017-18 onwards”.
3. CBIC. CGST Act, 2017, section 2(6): aggregate turnover. Same-PAN, all-India definition.
4. GSTN (mirrored by the Maharashtra GST Department). Advisory: time limit for reporting e-invoices on IRP, 5 November 2024. 30-day limit for AATO ₹10 crore and above from 1 April 2025.
5. CBIC. CGST Rules, 2017, rule 48: manner of issuing invoice. Sub-rules (4) and (5).
6. National Informatics Centre. e-Invoice System. Official IRP: IRN, signed invoice and QR code; 6-digit HSN note.
7. TaxGuru (CA Sandeep Kanoi). GST e-invoice in October 2026: ₹5 crore coverage and 30-day IRN reporting rule. Secondary, reviewed 11 October 2026: current position, exempt classes, ITC consequence.
8. Tally Solutions. How to cancel e-invoices in GST. Secondary: 24-hour window, no partial cancellation, credit/debit notes after that.
9. ClearTax. All about the GePP facility under e-invoicing. Secondary: limits of NIC’s offline GePP tool.

E-invoicing in one system, stock and orders in another?

If your invoices, GST data and operations don’t line up, we build finance tools and integrations that sit alongside your accountant’s workflow. See our accounting and finance software work.