GST ITC Auto-Restriction to GSTR-2B: What's Changing in GSTR-3B and How to Prepare

Introduction

If you have filed GSTR-3B in the last year, you have already lived through the first stage of GST's move toward a fully system-driven return. Since the July 2025 tax period, your outward liability figures in Table 3.1 and Table 3.2 have been locked and non-editable, pulled straight from GSTR-1 and GSTR-1A. Since October 2025, your Input Tax Credit in Table 4 has been auto-populated from GSTR-2B based on your Invoice Management System (IMS) actions - but you have still had the ability to manually adjust that figure before filing.

That last bit of manual flexibility is what is reportedly changing next. Multiple tax industry publications, citing Finance Ministry sourcing, describe a second phase - removing the ability to manually edit or override the auto-populated ITC figure in Table 4 - as targeted for around the July 2026 tax period. Some describe it as already effective; others describe it as still rolling out. We have not been able to locate a specific, dated GSTN advisory confirming it is fully live as of this writing, so we are presenting it here as an anticipated change you should prepare for now, not as a settled fact. We will note clearly, section by section, what is confirmed and operative today versus what is expected.

Either way, the direction is unambiguous: manual correction at the GSTR-3B filing stage is disappearing, table by table. The businesses that will handle this smoothly are the ones that shift their GST reconciliation earlier in the month, not the ones that wait to "fix it in GSTR-3B."

Current Status: What's Already Confirmed and Live

We recommend checking the official GST portal advisories at gst.gov.in directly before assuming this change is already in force for your filing this month.

What the Expected Change Actually Means

Right now, if your Table 4 ITC figure - auto-populated from GSTR-2B/IMS - doesn't match what you believe you're eligible for, you can still type in a different number before filing GSTR-3B. That override is the specific ability that is reportedly being removed. Once it is gone, whatever ITC your GSTR-2B and IMS actions support is what gets filed. Nothing more, nothing less.

In practical terms, this means the moment to fix an ITC mismatch stops being "at the time of filing GSTR-3B" and becomes "before the return period closes" - through IMS actions and vendor follow-up during the month, not adjustments on the last day.

The Table 3.1(d) Trap Businesses Are Already Missing

One detail that gets lost in the broader "GST is getting automated" narrative: Table 3.1(d) - inward supplies liable to reverse charge (RCM) - is not auto-populated. This includes import of services, purchases from unregistered vendors, and other notified RCM categories. Even as outward liability and ITC increasingly lock to auto-populated figures, RCM liability still has to be entered manually.

The common mistake: businesses claim ITC on RCM supplies in Table 4 (which may auto-populate correctly once GSTR-2B reflects it) but forget to separately declare the corresponding liability in Table 3.1(d). Under Rule 88C, that mismatch can trigger an automated notice. As locking tightens elsewhere, this manual field becomes the one place errors are most likely to slip through unnoticed.

What This Means for Your Monthly GST Workflow

Whether the ITC lock is already in force or still a few weeks away, the preparation is the same. Here's what changes in practice:

• Reconcile purchase register against GSTR-2B continuously, not just before filing. If your vendor hasn't filed their GSTR-1 by the 11th, their invoice won't reflect in your GSTR-2B for that period - and once ITC is locked, a late-filed invoice simply won't be available for you to claim until the following cycle.
• Act on IMS before the 14th of the month. Accept, reject, or keep pending every inward invoice showing in IMS. If you take no action, the invoice is treated as accepted by default - which can pull incorrect or disputed invoices into your eligible ITC without you noticing.
• Recompute GSTR-2B after every IMS action. An action taken in IMS doesn't retroactively update an already-generated GSTR-2B; you need to trigger recomputation to see the effect before filing.
• Reject bad credit notes in IMS, don't just ignore them. An unactioned credit note can reduce your ITC automatically once accepted by default.
• Correct outward-side errors through GSTR-1A before filing GSTR-3B, not after. Since Table 3.1/3.2 are already locked, GSTR-1A is your only correction window for that period.
• Keep manually entering Table 3.1(d) RCM liability every period - this table isn't part of the auto-population changes and needs a dedicated review step in your monthly checklist.

If your GST reconciliation process still happens on a spreadsheet the day before the due date, this is the moment to move it earlier in the cycle. Our GST reconciliation guide for GSTR-1, 3B, 2A and 2B covers the matching process in detail if you need a refresher on the fundamentals before adapting your workflow.

Why the Government Is Pushing This

The stated intent behind both phases of GSTR-3B locking is the same: reduce fake or inflated ITC claims by removing the ability to manually override system-computed figures. Industry estimates cited around this reform put revenue lost to fraudulent ITC claims at well over ₹2 lakh crore since GST's rollout - a scale the government has repeatedly flagged as the reason for moving toward a "verify before filing" model rather than an "enter and adjust" one.

For compliant businesses, the practical effect isn't a loss of legitimate credit - it's a shift in where accuracy has to happen. Instead of catching and fixing a mismatch at the filing stage, you now need clean data flowing in from your vendors and your own IMS actions throughout the month.

How GST Software Helps You Stay Ahead of This

Manually tracking IMS actions, GSTR-2B changes, and RCM entries across even a modest number of GSTINs becomes unmanageable once you're doing it every few days instead of once a month. CompuGst is built for exactly this shift - automated reconciliation between your purchase register and GSTR-2B, IMS action tracking, and RCM liability flagging.

Quick Preparation Checklist

• Confirm the current status of Table 4 ITC locking on the official GST portal before assuming it's already mandatory for this period.
• Set a recurring reminder to review and action IMS entries by the 14th of every month.
• Reconcile your purchase register against GSTR-2B before, not after, GSTR-3B filing.
• Follow up with vendors who consistently file GSTR-1 late, since their invoices miss your GSTR-2B window.
• Build a separate manual review step for Table 3.1(d) RCM liability every period.
• Route all outward-side corrections through GSTR-1A before the GSTR-3B due date.

Frequently Asked Questions

Is GST ITC in GSTR-3B already locked to GSTR-2B?

Partially. ITC in Table 4 has been auto-populated from GSTR-2B and IMS actions since the October 2025 tax period. Removing the ability to manually edit that auto-populated figure is reported as targeted for around July 2026, but we recommend confirming the current status via an official GST portal advisory before treating it as already in force.

What is already locked in GSTR-3B today?

Outward liability in Table 3.1 and Table 3.2 has been non-editable since the July 2025 tax period, sourced directly from GSTR-1, GSTR-1A, and IFF.

Can I still correct my outward liability after filing GSTR-1?

Yes, but only through GSTR-1A, filed before you submit GSTR-3B for that period. Table 3.1/3.2 in GSTR-3B itself cannot be edited directly.

Is Table 3.1(d) RCM liability auto-populated?

No. Reverse charge liability on import of services, unregistered vendor purchases, and other notified categories must still be entered manually, even as other tables move toward full automation.

What happens if I don't action an invoice in IMS?

If no action is taken by the due date, the invoice is treated as accepted by default and flows into your GSTR-2B as eligible ITC. This makes it important to actively reject or pend disputed invoices rather than leaving them unactioned.

Conclusion

Whether ITC locking in GSTR-3B is already fully in force or still a few weeks from going live, the direction is clear and it isn't reversing. The businesses that will feel the least friction are the ones that stop treating GST reconciliation as a once-a-month, pre-filing task and start treating it as a continuous one - reviewing IMS regularly, chasing vendors on filing timelines, and keeping RCM entries current. Waiting to "adjust it in GSTR-3B" is a habit that's already partly obsolete, and reportedly about to become fully obsolete.

If you're managing this across multiple GSTINs or client entities, CompuGst can move that reconciliation earlier in your cycle so nothing depends on a last-day manual fix.

Disclaimer

This article is for informational purposes only. Compliance requirements, due dates, and regulatory provisions are subject to change based on government notifications. Please verify all deadlines and filing requirements on the relevant official portals before acting.