GSTR-3B Filing: 8 Common Errors That Lead to GST Notices

I file GSTR-3B for 80+ clients every month. After years of doing this, I can tell you the errors that consistently lead to notices from the department. Avoid these and you will avoid 90% of GST issues.

ERROR 1: ITC CLAIMED EXCEEDS GSTR-2B
This is the biggest trigger. If your GSTR-3B ITC claim is higher than what appears in auto-populated GSTR-2B, you will get a notice. Always reconcile before filing. If a vendor has not uploaded their invoice, do not claim that ITC yet.

ERROR 2: OUTWARD SUPPLY MISMATCH WITH GSTR-1
If your GSTR-1 shows Rs 50 lakh outward supplies but GSTR-3B shows Rs 45 lakh — the system flags it automatically. This usually happens when credit notes are not properly accounted, or when amendments are filed incorrectly.

ERROR 3: WRONG HEAD — IGST vs CGST/SGST
Inter-state supply = IGST. Intra-state supply = CGST + SGST. Getting this wrong is surprisingly common, especially when a client has multi-state operations. The tax amount may be the same, but filing under the wrong head creates reconciliation problems.

ERROR 4: NOT REVERSING INELIGIBLE ITC
Section 17(5) lists blocked credits — motor vehicles, food & beverages, personal consumption, etc. If your vendor charges GST on these, you cannot claim ITC. Many clients claim all ITC from GSTR-2B without checking eligibility. The department catches this in annual reconciliation.

ERROR 5: LATE FILING WITHOUT INTEREST
If you file GSTR-3B after the due date (20th of next month for monthly filers), interest at 18% per annum applies on the net tax liability. Many people file late but do not calculate and pay the interest — leading to a separate interest demand later.

ERROR 6: NOT REPORTING RCM SUPPLIES
Reverse charge supplies must be reported separately in Table 3.1(d) of GSTR-3B. Forgetting to report RCM and also forgetting to pay it is a double default.

ERROR 7: ADVANCE PAYMENT NOT ACCOUNTED
If you receive advance payment for a supply, GST is payable at the time of receipt of advance (for services). Many businesses only account for GST at the time of invoice, missing the advance liability.

ERROR 8: NIL RETURN NOT FILED
Even if you have zero transactions in a month, you must file a NIL GSTR-3B. Non-filing leads to late fee accumulation and eventually, cancellation of GST registration. I have seen clients accumulate Rs 50,000+ in late fees just from not filing NIL returns.