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A junior accountant finds the GSTR-1 HSN summary total does not equal the sales report for the month.
Table 12 totals net supplies by HSN or SAC, unit and B2B or B2C split. Differences come from credit-note netting, units, missing codes, period cut-off and rounding.
A monthly bridge from sales report total to Table 12 total listing credit notes, period shifts, non-GST items and rounding, with codes picked from the item master.
Table 12 explained to the rupee before filing, and consistent with the GSTR-1 invoice tables.
The HSN summary in GSTR-1 adds up your month’s sales by HSN or SAC code, unit and value. It often differs from your sales report because the two count different things: one may net off credit notes and the other may not, items can share a code, units may not match, or some invoices fall in a different month. The difference is usually explainable line by line.
The HSN summary is Table 12 of GSTR-1, due by the 11th of the following month (or the 13th after the quarter for QRMP filers).
What usually causes the mismatch?
| Cause | What you see | Fix |
|---|---|---|
| Credit notes netted in one report only | HSN total lower than sales report | Decide one basis; Table 12 shows net supplies |
| Two items share one HSN code | Fewer HSN rows than items | Nothing wrong; compare at code level, not item level |
| Units differ (pieces vs kilograms) | Quantity off, value fine | Use the unit code the portal expects, from the item master |
| B2B and B2C split wrong | Totals right, tabs wrong | Tag each invoice by buyer GSTIN |
| Missing or invalid code on items | Value missing from Table 12 | Add codes to the item master from the portal list |
| Non-GST or exempt items in the sales report | Sales report higher | Report exempt supplies in Table 12 with their code; keep non-GST items out |
| Invoices dated in another month | Timing gap | Check the cut-off for the last two days of the month |
| Rounding on each line | Gap of a few rupees | Accept; round at line level consistently |
Why does the HSN summary now separate B2B and B2C sales?
From 2025, GSTN’s Phase III of HSN reporting split Table 12 into a B2B tab (sales to registered buyers) and a B2C tab (sales to unregistered buyers). Codes are picked from a drop-down instead of typed. If your GSTR-1 has B2B invoices, the B2B tab cannot be blank. This change caught many businesses whose software sent one combined summary.
Should the HSN totals equal the invoice tables of GSTR-1?
They should agree, after allowing for credit and debit notes and advances. The invoice tables (B2B, B2C large, B2C others, exports) less the net of credit and debit notes should equal the Table 12 total. The portal now checks this, initially as a warning. A gap you cannot explain is worth fixing before filing.
Worked example: a ₹48,000 gap
A Nagpur electronics trader’s October sales report shows ₹14,60,000 of taxable sales. The Table 12 summary shows ₹14,12,000.
| Item | Amount |
|---|---|
| Sales report, taxable value | ₹14,60,000 |
| Less credit notes issued in October (netted in Table 12, not in the sales report) | ₹48,000 |
| Expected Table 12 total | ₹14,12,000 |
| Actual Table 12 total | ₹14,12,000 |
| Unexplained difference | Nil |
₹14,60,000 minus ₹48,000 equals ₹14,12,000. The fix is not to change either figure but to keep this bridge on file. If the trader had found, say, ₹14,05,000 in Table 12, the remaining ₹7,000 would point to a missing code or an invoice in the wrong month.
A five-minute check before filing
- Export the sales report and the Table 12 preview for the month.
- Subtract credit notes and add debit notes.
- Compare at code level and list any code only in one report.
- Check the B2B and B2C tabs against buyer GSTINs.
Key rules to remember
- HSN digits follow Notification 78/2020: 4 digits up to ₹5 crore of turnover, 6 digits above ₹5 crore.
- Credit notes reduce Table 12 in the month issued; under Section 34 they must be declared by 30 November following the financial year.
- Tax paid late carries interest at 18 percent a year under Section 50 of the CGST Act.
What to read next
- Next in this series: GSTR-1 vs GSTR-3B reconciliation failure modes
- Getting codes right: How do I find the right HSN code for my product? and HSN code vs SAC code
- GST reconciliation software: GST outward reconciliation (GSTR-1 and GSTR-3B) leads the TransactIG GST roadmap.