A mismatch between GSTR-1 and GSTR-3B sales can occur even without amendments, due to several common reasons:
✅ Possible Reasons:
- Timing Differences:
- Invoices reported in GSTR-1 of one month but considered in GSTR-3B of a different month.
- B2C vs. B2B Classification Errors:
- Misreporting of B2B invoices as B2C or vice versa, affecting auto-population in GSTR-3B.
- Wrong Table Entries:
- Sales reported in Table 3.1(a) (taxable supplies) in 3B may differ from GSTR-1 summary tables (e.g., 4A, 5, 6B, etc.).
- Zero-Rated Supplies (Exports/SEZ):
- Declared correctly in GSTR-1 but missed or misclassified in Table 3.1(b) of GSTR-3B.
- Credit/Debit Notes:
- Rounding-Off Errors:
- Small mismatches due to rounding off at invoice level in GSTR-1 vs aggregate in GSTR-3B.
- Technical/Portal Errors:
- Occasional technical glitches during filing or data sync issues.
You can prepare a reconciliation statement format to identify the root cause.
Here’s a GSTR-1 vs. GSTR-3B Sales Reconciliation Format to help you identify the mismatch causes and correct them systematically:
Particulars
|
GSTR-1 Amount
|
GSTR-3B Amount
|
Difference
|
Remarks/Reason
|
B2B Invoices (Registered)
|
|
|
|
Check if all B2B invoices were included
|
B2C Large (Invoice Value > ₹2.5L)
|
|
|
|
Confirm proper classification
|
B2C Small (Consolidated)
|
|
|
|
Verify summary matches books
|
Credit Notes
|
|
|
|
Ensure impact shown in both forms
|
Debit Notes
|
|
|
|
Same treatment as credit notes
|
Exports (with/without payment of tax)
|
|
|
|
Match 3.1(b) of GSTR-3B with Table 6 of GSTR-1
|
SEZ Supplies
|
|
|
|
Check if reported under correct table
|
Advance Received & Adjusted
|
|
|
|
Verify correct adjustments done
|
Total Taxable Turnover
|
|
|
|
Auto-calculate
|
✅ Steps to Use the Format:
- Export GSTR-1 and GSTR-3B data for the period from the GST portal.
- Compare each category side by side.
- Note any classification or timing differences.
- Check if any invoices were missed in either form.
- Summarize the total mismatch and document corrective actions (e.g., adjust in the next return, file amendment if allowed).
***