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Comprehensive Guide to E-Invoicing Under GST

GST & E-Invoicing1 April 2025·18 min read·By CA Mudragada Srinivas

An in-depth walk-through of e-invoicing under GST — applicability, phased turnover thresholds, timing rules, the 30-day reporting window, cancellations and ITC implications.

Understanding E-Invoice: Definition and Regulatory Framework

What is E-Invoice?

The term "E-Invoice" is not formally defined in the GST Act or Rules. The framework refers to "Invoice in terms of Rule 48(4)" when addressing e-invoicing matters. An e-invoice is a digitally generated and registered invoice issued in compliance with the prescribed format established by the GST authorities.

E-invoicing represents a fundamental shift in how businesses document Business-to-Business (B2B) transactions under GST. Unlike traditional paper invoices, e-invoices are electronically generated, registered on a centralized portal, and assigned a unique Invoice Reference Number (IRN) embedded with a QR code — making them tamper-proof and transparent.

Key Advantages and Benefits of E-Invoicing

  1. Real-time information transmission to the government for live monitoring of economic activity.
  2. Standardized GST-INV-01 format based on the Universal Business Language (UBL) standard.
  3. Elimination of fake invoicing in taxable B2B supplies.
  4. Prevention of round-tripping — circular routing of the same invoice to inflate ITC.
  5. Curbs fake ITC claims since every B2B invoice is registered and trackable.
  6. Stops fraudulent refund claims based on fake invoices.
  7. Coverage of low-value B2B supplies below ₹50,000 that previously escaped e-way bills.
  8. All B2B service supplies covered, regardless of value.
  9. Removes regional language barriers during Section 68 verification.
  10. Provides irrefutable proof for banks during bill discounting and recovery of dues.
  11. Acts as authentic evidence for claiming receivables in legal proceedings.

Phased Implementation and Turnover Thresholds

The e-invoicing mandate has been implemented in six phases, gradually expanding coverage so businesses can adapt incrementally.

PhaseApplicable DateTurnover Threshold (from 01.07.2017)Notification
Phase 11 Oct 2020₹500 crore and above61/2020 – Central Tax
Phase 21 Jan 2021₹100 crore and above88/2020 – Central Tax
Phase 31 Apr 2021₹50 crore and above5/2021 – Central Tax
Phase 41 Apr 2022₹20 crore and above1/2022 – Central Tax
Phase 51 Oct 2022₹10 crore and above17/2022 – Central Tax
Phase 61 Aug 2023₹5 crore and above10/2023 – Central Tax

Calculating Aggregate Annual Turnover (AATO)

Aggregate turnover is calculated on a financial year basis (April–March). Taxes collected are never included for determining e-invoicing applicability.

#Nature of SupplyTreatment
1All Taxable SuppliesIncluded
2All Exempted SuppliesIncluded
3Export of Goods or ServicesIncluded
4Interstate supplies between persons with same PANIncluded
5Nil-rated SuppliesIncluded
6Non-GST SuppliesIncluded
7Inward supplies on which tax is payable under RCMExcluded
8CGST, SGST, IGST, CessExcluded

Persons Exempted from the E-Invoicing Mandate

  1. Insurers (Rule 54(2) of CGST Rules, 2017)
  2. Banking Companies (Rule 54(2))
  3. Non-Banking Financial Companies (NBFCs)
  4. Goods Transport Agencies operating road transportation
  5. Passenger Transportation Services
  6. Cinema and Multiplex Admissions
  7. Government Departments (B2G Supplies)
  8. Local Authorities
  9. Special Economic Zone (SEZ) Units

When E-Invoicing is Mandatory vs. Optional

E-Invoices Must Be Issued For:

E-Invoices Must NOT Be Issued For:

Timing Requirements: When to Generate E-Invoices

Timing is governed by Section 31 of the CGST Act, 2017, Rule 47 (timing) and Rule 48(4) (format and mode). There is no grace period prescribed for uploading invoices to the IRP — invoices must be reported immediately on issue.

The 30-Day Reporting Rule (Effective 1 April 2025)

Effective 1 April 2025, businesses with AATO of ₹10 crore or more must report B2B e-invoices to the IRP within 30 days from the invoice date. Example: an invoice dated 15 April 2025 must be reported by 15 May 2025. The IRP automatically rejects invoices older than 30 days.

AdvisoryApplicable DateAATO ThresholdTime LimitStatus
Initial (6 Apr 2023)1 May 2023₹100 crore+7 daysDeferred till Aug 2023
Revised (6 Sep 2023)1 Nov 2023₹100 crore+30 daysImplemented
Latest (10 Nov 2024)1 Apr 2025₹10 crore+30 daysCurrently being implemented

Cancellation and Amendment of E-Invoices

Method 1 — Cancellation at IRP Level

Within 24 hours of IRN generation. The invoice can be cancelled completely but cannot be modified, and must be cancelled before any e-way bill is issued.

Method 2 — Modification at GST Portal

After 2 days of IRN generation but before filing of GSTR-1. Cannot be cancelled here, and corrections trigger scrutiny under Section 61.

Method 3 — Credit Note / Debit Note

Within the time limit specified under Section 37(3). Once supply has taken place, no edit/delete of the IRN is available — a credit or debit note is the only remedy.

E-Invoice and E-Way Bill: Sequencing

  1. An e-invoice with IRN must be generated before any e-way bill for the same supply.
  2. The e-way bill can be generated directly from the e-invoice portal using the IRN.
  3. The IRN must be embedded in the e-way bill for validation.
  4. Part A of the e-way bill is auto-populated from invoice data uploaded to the IRP (Rule 138A(3)).
  5. Cancellation and validity extension of e-way bills are managed only via the e-way bill portal.
  6. There is no time limit to generate the e-way bill, but it can only be generated for invoices issued in the preceding 180 days (effective 1 Jan 2025).

Data Retention and Backup

Penalties for Non-Compliance

Non-compliance with e-invoicing attracts graduated penalties under Sections 122, 125 and 129 (monetary) and Section 132 (criminal — imprisonment) for gross negligence, deliberate false invoices or systematic circumvention.

"The only difference between death and taxes is that death doesn't get worse every time Congress meets."

Will Rogers