GSTR-3B Return Filing: The Complete Guide (FY 2025-26)

Mastering monthly returns, handling new "hard-locking" rules, and automating compliance within SAP.

GSTR-3B is the backbone of India's GST compliance framework. Every regular registered taxpayer is required to file a self-declared summary return on a monthly basis (or quarterly under the QRMP scheme). Unlike GSTR-1, which details your sales, GSTR-3B is where you officially declare your tax liability, claim Input Tax Credit (ITC), and pay the tax to the government.

With the recent 2025 regulatory updates, particularly the Invoice Management System (IMS) and the hard-locking of auto-populated data, manually filing GSTR-3B has become a high-risk activity.

In this guide, we break down everything you need to know about GSTR-3B, due dates, late fees, and how SAP Cockpit Solutions can automate your reconciliation to ensure 100% accuracy.

1. What is GSTR-3B?

GSTR-3B is a simplified summary return for inbound and outbound supplies. It is a "payment return," which discharges the tax liability.

Key Components of GSTR-3B:

• Table 3.1: Details of outward supplies (sales) and inward supplies liable to reverse charge (RCM).
• Table 3.2: Details of interstate supplies made to unregistered persons, composition dealers, and UIN holders.
• Table 4: Eligible Input Tax Credit (ITC), Critical for SAP users.
• Table 5: Values of exempt, nil-rated, and non-GST inward supplies.
• Table 6.1: Payment of tax (cash vs. credit utilization).

2. Who Needs to File GSTR-3B?

Every person registered under GST must file GSTR-3B, including:

• Regular Taxpayers
• Casual Taxable Persons
• Taxpayers under the QRMP Scheme (Quarterly filing)

Exceptions (Who does NOT file):

• Composition Dealers (File CMP-08/GSTR-4)
• Input Service Distributors (ISD)
• Non-resident taxable persons (File GSTR-5)
• OIDAR service providers

3. Due Dates for GSTR-3B (FY 2025-26)

Missing these dates attracts late fees and an 18% interest penalty.

> Cat A: Chhattisgarh, MP, Gujarat, Maharashtra, Karnataka, Goa, Kerala, TN, Telangana, AP.

> Cat B: All other states and UTs.

4. The Critical Challenge: GSTR-2B vs. GSTR-3B Reconciliation

Since 2022, claiming ITC in GSTR-3B is limited to the ITC shown on your GSTR-2B statement. You cannot claim more than your suppliers have filed.

The "Hard-Locking" Update (2025)

The GSTN has switched to hard-locking auto-populated data. This means that the ITC figures that flow from GSTR-2B to GSTR-3B (Table 4) will no longer be editable.

• The Risk: If the Purchase Register (PR) in SAP does not match the GSTR-2B, your ITC will be blocked or you will receive demand notice.
• The Solution: You need a robust mechanism to reconcile your Purchase Register (PR) vs. GSTR-2B before the filing date.

Expert Advice: Manual reconciliation in Excel is prone to mistakes. For SAP-based enterprises, an embedded solution is the only way to ensure data integrity.

Check out our guide on GSTR-2B Reconciliation with Purchase Register using SAP Automation to see how to automate this daily.

5. How to File GSTR-3B (The Smart Way)

Step 1: Finalize Outward Supplies (GSTR-1)

Your liability in GSTR-3B (Table 3.1) is automatically populated from your GSTR-1. To avoid liability mismatches, ensure that your GSTR-1 is free of errors.

• Read More: GSTR-1 Return Explained: A Comprehensive Guide.

Step 2: Handle Invoice Management System (IMS) Actions

With the new IMS, invoices must be accepted, rejected, or kept pending. These actions have a direct impact on your GSTR-2B and, consequently, your GSTR-3B ITC availability.

• Deep Dive: GST IMS Reconciliation & SAP Automation.

Step 3: Auto-Reconciliation of ITC (The Sepfust Approach)

Instead of downloading JSON files and dealing with VLOOKUPs, use Sepfust's Cockpit Solution.

• How it works: Our solution integrates with your SAP system. It retrieves GSTR-2B data via API and reconciles it line by line with your SAP Purchase Register.
• Benefit: It detects missing invoices, mismatches, and ineligible ITC automatically.
• As a result, you receive a "Clean ITC" figure that is perfectly consistent with government records.

Discover the Solution: Auto ITC Reconciliation Cockpit, This cockpit solution helps in the reconciliation of PR vs. GSTR-2A/2B within the SAP systems only.

Step 4: Payment and Offset

Once the liabilities and ITC have been confirmed, offset the liability with the available credit (Electronic Credit Ledger). Any outstanding balance must be paid in cash via challan (Electronic Cash Ledger).

6. Late Fees and Interest (Updated 2025)

Late Fees (per day of delay):

• Nil Return: ₹20 per day (₹10 CGST + ₹10 SGST).
• Others: ₹50 per day (₹25 CGST + ₹25 SGST).
• Max Cap: Varies based on turnover (ranges from ₹500 to ₹10,000).

Interest on Delayed Payment:

• 18% p.a. on the Net Tax Liability (Tax to be paid in cash) if filed after the due date.
• Note: Interest is calculated from the day following the due date until the date of actual payment.

7. Why SAP Cockpit Solutions?

For large enterprises, "managing" GST is not enough; you must "automate" it. Sepfust provides dedicated SAP Cockpit Solutions that eliminate external tools and data security risks.

• Single Dashboard: Manage GSTR-1, GSTR-2B, IMS, and GSTR-3B from one SAP screen.
• Vendor Compliance: Automatically block payments to vendors who haven't filed their returns (checking GSTR-2A/2B status in real-time).
• Audit Trail: Maintain a digital trail of every reconciliation action for departmental audits.

Ready to Automate?

Don't let manual filing errors lead to GST notices.

• Explore: Auto ITC Reconciliation for SAP
• Learn: GSTR-2B vs Purchase Register Automation

Frequently Asked Questions (FAQs)

Q1: Can I revise GSTR-3B after filing?

No, GSTR-3B cannot be revised. Any errors must be adjusted in the subsequent month’s return or through GSTR-1A (for liability corrections). This makes accurate GSTR-1 filing crucial.

Q2: What happens if I have ITC in SAP but it's not in GSTR-2B?

You cannot claim it in GSTR-3B. You must follow up with the vendor to file their GSTR-1/IFF. Sepfust's Cockpit Solution can automate these vendor email triggers.

Q3: Is IMS mandatory for GSTR-3B?

Yes, actions taken in the Invoice Management System (IMS) will determine the final ITC available in GSTR-2B, which then auto-populates your GSTR-3B. Learn more about IMS Automation here.