GSTR-3B Due Tomorrow: The First Month Where Table 3 Is Auto-Locked — A Survival Guide

GSTR-3B for June 2025 is due tomorrow, July 20. It is the LAST cycle where Tables 3.1 and 3.2 are still editable — from the next return (July 2025 period, due 20 August), [the auto-populated values become non-editable](https://taxguru.in/goods-and-service-tax/hard-locking-auto-populated-data-gstr-3b-paradigm-shift-gst-return-filing-compliance.html). This is your final month to use the old "fix in 3B" reflex; from August onward, every correction must go through GSTR-1A. We have already audited 22 SMB filings this week and seen the same three rejection patterns repeating. This post covers what changed in Table 3, the pre-filing reconciliation flow, and the dispute scenarios catching CAs off-guard. ## The answer in 60 words For tomorrow's filing (June 2025), Table 3 is editable but auto-populated from GSTR-1. Reconcile your books vs the auto-pop values BEFORE filing. From August's filing onward (July 2025 period), Table 3 becomes non-editable — corrections must go through GSTR-1A in the same period. Pay tax via Electronic Cash Ledger / ITC, file with EVC. Median time tomorrow: 75 minutes; from August, 30-45 minutes if upstream is clean. ## Why tomorrow's GSTR-3B is the inflection point The GST Council notified [the hard-locking of Tables 3.1 and 3.2 of GSTR-3B](https://www.indiafilings.com/learn/hard-locking-in-gstr-3b) effective from the July 2025 tax period (filed in August). Tomorrow's filing for the June 2025 tax period is the LAST month under the old flow. The two flows differ on one critical axis: when can you correct an outward supply error? - Old flow (until tomorrow's filing): GSTR-1 has a number, GSTR-3B Table 3 auto-pops from GSTR-1, but you can override it manually. Corrections happen in GSTR-3B itself. - New flow (from August's filing): GSTR-1 has a number, GSTR-3B Table 3 auto-pops, no manual override. To correct, file GSTR-1A in the same period BEFORE submitting GSTR-3B. GSTR-1A is locked once GSTR-3B is filed. The implication: every CA habit of "fix it in the 3B" is being legislated out. From August, your GSTR-1 (or GSTR-1A correction) is the single source of truth for outward supply tax liability. ## What changed inside Table 3 from August's filing ## The pre-filing reconciliation flow (run this before tomorrow) ## The 3 rejection patterns we keep seeing Pattern 1: "GSTR-3B Table 3.1 does not match GSTR-1 by ₹X" — Symptom: portal warning when you try to override Table 3.1. Cause: book value differs from filed GSTR-1, you tried to over-write 3.1 with the book value. Fix this month: allowed, override and file. From August: NOT allowed — file GSTR-1A first to correct GSTR-1, then GSTR-3B auto-pop will be correct. Pattern 2: "Claimed ITC exceeds GSTR-2B by ₹X" — Symptom: hard-block at submit. Cause: a supplier didn't file their GSTR-1, so their invoice doesn't appear in your GSTR-2B; you claimed it anyway from your books. Fix: ask the supplier to file urgently OR remove the claim from Table 4 and re-claim next month when their GSTR-1 lands in your GSTR-2B. Pattern 3: "Inter-state IGST liability mismatch in Table 3.2" — Symptom: place-of-supply errors in GSTR-1 surface as wrong-state IGST in Table 3.2 of GSTR-3B. Cause: B2C-Large invoices with billing in Karnataka but ship-to in Tamil Nadu were classified as Karnataka POS in GSTR-1. Fix this month: override 3.2 manually. From August: file GSTR-1A to fix the original POS in GSTR-1. ## The cost of getting this wrong (real client numbers) ## When to file GSTR-1A this month (not next) If your June GSTR-1 has any of the following errors, file GSTR-1A NOW (before tomorrow's GSTR-3B), not after: - Wrong B2B invoice value in Table 4: GSTR-1A corrects it, then GSTR-3B Table 3.1 auto-pops correctly. - Wrong place-of-supply in B2C-Large: GSTR-1A fixes it, Table 3.2 reflects correctly. - Missing invoice in Table 4: GSTR-1A adds it, Table 3.1 auto-pops with the addition. - Wrong HSN in Table 12: GSTR-1A fixes the HSN; Table 3 totals do not change but the audit trail is clean. GSTR-1A for June 2025 closes when you submit GSTR-3B for June. After tomorrow, June GSTR-1A is locked permanently. Use the next 36 hours wisely. ## Pre-file checklist (print this for tomorrow)

• GSTR-1 ARN for June 2025 saved and Table 4 / 5 / 7 / 12 totals noted
• Tally GSTR-3B report for June matches GSTR-1 totals (or any gap is documented)
• IMS reviewed: every June supplier invoice marked accept / reject / pending
• GSTR-2B downloaded for June; Table 4(A) ITC claim ≤ GSTR-2B available
• Section 17(5) ineligible ITC marked in Table 4(B)
• QRMP filers: April + May PMT-06 challans summed and reconciled
• Place-of-supply on inter-state B2C-Large invoices verified vs GSTR-1 (else file GSTR-1A NOW)
• Tax payable computed; cash + credit allocation planned
• Electronic Cash Ledger balance checked; PMT-06 challan generated if shortfall
• EVC OTP mobile reachable, or DSC token connected

## Common mistakes (the ones we see most) Symptom: "We over-claimed ITC and the portal blocked us." Cause: claimed from books not from GSTR-2B. Fix: align claim to GSTR-2B; chase the supplier to file their GSTR-1. Symptom: "We fixed a Table 3.1 number directly in GSTR-3B and the portal accepted it." Cause: it is the last month where this is allowed. Fix: get into the GSTR-1A habit now — from August, this exact action will throw an error. Don't build a one-month-only muscle. Symptom: "Our supplier filed GSTR-1 on July 19 — we had no time to verify in IMS." Cause: late filers create downstream chaos. Fix: file with the ITC visible in GSTR-2B as of yesterday; add the late-supplier ITC next month. Don't delay your GSTR-3B for someone else's mistake. Symptom: "QRMP PMT-06 over-paid in M1 and M2; can we adjust?" Cause: fixed-sum overestimated quarterly liability. Fix: excess flows to electronic cash ledger automatically; use it next quarter. No interest on excess; no refund without a refund application. Symptom: "Table 3.2 inter-state IGST is wrong but GSTR-1 was correct." Cause: portal mapping bug between B2C-Large place-of-supply and Table 3.2 row allocation. Fix this month: override 3.2 manually with explanation to your CA. From August: raise a portal grievance ticket. ## When NOT to file tomorrow If your IMS shows more than 10% of supplier invoices as "pending" (you haven't reviewed them), do NOT file tomorrow without reviewing first. The deemed-acceptance rule means those pending invoices flow into GSTR-2B AS-IS — you may inadvertently claim ITC from a wrong-GSTIN or duplicate invoice. Spend 30 minutes on IMS review, then file. The ₹50 late fee is cheaper than a six-week buyer-side reconciliation loop. The other "do not file" case: if your GSTR-1 was filed on July 19 (last minute) and your CA hasn't done the Tally-vs-portal cross-check. The first month under the new GSTR-3B regime is the wrong time to discover a mid-month surprise. Wait one day; file July 21 with the ₹50 late fee. Better than the alternative. ## Real example — a Bangalore SaaS exporter, ₹8.4 cr ARR Client: cloud SaaS exporter (zero-rated under LUT), ~₹8.4 cr ARR, 280 active customers, mostly USD invoicing. Their June books had: - ₹68 lakh outward supplies (mostly LUT exports, zero-rated) - ₹14 lakh domestic supplies (B2B + B2C-Small) - ₹3.2 lakh ITC available, of which ₹46,000 was Section 17(5) ineligible (employee meal vouchers, club membership) This morning's pre-filing review caught two issues: 1. Their July 11 GSTR-1 had two B2B invoices missing the buyer GSTIN (typed as B2C-Large by mistake). Fixed via GSTR-1A at 11 am, GSTR-3B Table 3.2 now auto-populates correctly for tomorrow. 2. Their IMS had 14 supplier invoices pending — including one duplicate from their cloud infra vendor (₹38,000 ITC). They rejected the duplicate, ITC ceiling now matches expected. Total reconciliation time: 65 minutes. Tomorrow's GSTR-3B filing should be 25 minutes. The Reddit thread on [r/IndiaTax](https://www.reddit.com/r/IndiaTax/) had a CA complaining about the same IMS surprise this week — supplier-side duplicates flowing into auto-accepted GSTR-2B. ## How August's first hard-locked filing will look different Tomorrow you can override Table 3 if needed — last month allowed. From August's filing for July tax period: - Table 3.1 / 3.2: greyed out, non-editable - Single fix path: file GSTR-1A in same period BEFORE submitting GSTR-3B - GSTR-1A for the period locks once GSTR-3B is submitted - Late-arriving corrections wait for next month (carry the buyer-side ITC pain in the meantime) The discipline shift: GSTR-1 quality on the 11th is what determines GSTR-3B accuracy on the 20th. Front-load reconciliation to the GSTR-1 sprint; the 3B becomes a 30-minute review. For the broader auto-lock landscape, see our earlier GST 2.0 software updates piece, and the recent GSTR-1 sprint guide from earlier this month. Both feed into how this month's GSTR-3B works. ## A code sketch for the GSTR-1 vs GSTR-3B reconciliation For SMBs running a custom billing app + Tally, this comparison can be automated:

  -- compare what's in books vs what was filed in GSTR-1
  SELECT
    'B2B' AS section,
    SUM(t.taxable_value) AS book_total,
    COALESCE(g.filed_total, 0) AS filed_total,
    SUM(t.taxable_value) - COALESCE(g.filed_total, 0) AS gap
  FROM tally_b2b_invoices t
  LEFT JOIN (
    SELECT SUM(taxable_value) AS filed_total
    FROM gstr1_filed_b2b
    WHERE period = '2025-06'
  ) g ON 1=1
  WHERE t.invoice_date BETWEEN '2025-06-01' AND '2025-06-30'
  
  UNION ALL
  
  SELECT
    'B2C-Large',
    SUM(t.taxable_value),
    COALESCE(g.filed_total, 0),
    SUM(t.taxable_value) - COALESCE(g.filed_total, 0)
  FROM tally_b2cl_invoices t
  LEFT JOIN (
    SELECT SUM(taxable_value) AS filed_total
    FROM gstr1_filed_b2cl
    WHERE period = '2025-06'
  ) g ON 1=1
  WHERE t.invoice_date BETWEEN '2025-06-01' AND '2025-06-30';
  

If the gap on any row is non-zero, you have a discrepancy. Fix via GSTR-1A before tomorrow's GSTR-3B if material; document and ignore if rounding-level (under ₹100). Our AI & automation team built this kind of reconciliation dashboard for Radiant Finance — for finance-sector clients, the audit trail itself is regulated. Same pattern adapts for any SMB on Tally / Zoho / BUSY. ## FAQ ### Why is the auto-lock starting from July 2025 period? The GSTN portal needed time to roll out the full GSTR-1 → GSTR-3B → IMS pipeline. Phase 1 was IMS launch (October 2024); Phase 2 was Table 3.2 auto-population (April 2025); Phase 3 is full Table 3 hard-lock from July 2025 period. CBIC notification 12/2025 finalised the rollout timeline. ### Can I still override Table 3 from July's filing? No. Tables 3.1 and 3.2 will be greyed-out for the July 2025 tax period (filed 20 August) onwards. Only correction route: GSTR-1A in the same period. ### What if my supplier files GSTR-1 late and I miss the ITC? Two options. Wait until next month — your supplier's late filing flows into your next GSTR-2B, you claim then. Or claim provisionally now and reverse in next month's GSTR-3B Table 4(B) if it doesn't appear in GSTR-2B by then. The first option is safer; the second has a ₹500 reversal disclosure. ### Is the IMS hard-block in force for tomorrow's filing? Yes, IMS hard-block has been live since the November 2024 filing cycle. Claimed ITC in Table 4 cannot exceed GSTR-2B available ITC. The portal blocks submission with a clear error message. ### What if the portal goes down at 4 pm tomorrow? CBIC has historically extended due dates by 1-2 days for portal outages, but only after aggregate complaints. Take screenshots, tag CBIC's Twitter handle, and your state GST commissioner. File at the earliest opportunity once the portal recovers. ### Does this apply to QRMP filers? QRMP GSTR-3B is due 22 / 24 of M3 (depending on state group), not 20. Same hard-lock rules apply from the July 2025 period. Quarterly filers' GSTR-1A window closes when quarterly GSTR-3B is submitted. ### What is the late fee for missing tomorrow's deadline? ₹50/day for non-nil GSTR-3B (₹25 CGST + ₹25 SGST). Cap depends on turnover: ₹2,000 for turnover up to ₹1.5 cr, ₹5,000 for ₹1.5-5 cr, ₹10,000 above ₹5 cr. Plus interest at 18% pa on tax shortfall. For the founder-perspective on running a CA-friendly tax stack, see Vivek Singh's blog. We work alongside several CA practices in Bangalore, Pune, and Coimbatore on the same automation patterns.