GSTR-1 Table 12 and Table 13 Errors: Fixing HSN Dropdown, B2B/B2C Split and Documents Issued
By GST Reco Pro
GST Reco Pro builds browser-based tools for GST and TDS reconciliation, used by Chartered Accountants and corporate tax teams across India.
Since the May 2025 return period, GSTR-1 Table 12 takes HSN codes from a dropdown, split into separate B2B and B2C tabs, and Table 13 (documents issued) is mandatory. Here are the errors that stop filing or trigger warnings, and how to reconcile Table 12 before you file.
Phase III of HSN reporting in GSTR-1 changed the HSN summary from a free-text table into a validated one. From the May 2025 return period, three changes apply to GSTR-1 and GSTR-1A: HSN codes are picked from a dropdown instead of typed, Table 12 is split into separate B2B and B2C tabs, and Table 13 (documents issued) became mandatory. The portal also cross-checks Table 12 against the values reported elsewhere in the return.
Most practices adapted in the first few months. The errors that remain are mostly structural: they come from how the billing system builds the HSN summary, not from the person filing.
What the portal checks now
| Requirement | What goes wrong |
|---|---|
| HSN chosen from the dropdown master | Codes in the billing system that are not in the master, or are at the wrong level of detail |
| Minimum digits: 4 for AATO up to ₹5 crore, 6 above ₹5 crore | Item masters still on 4 digits after the business crossed ₹5 crore |
| Separate B2B and B2C tabs | A single combined summary uploaded, or B2C values put on the B2B tab |
| B2B values in Table 12 agree with B2B values in other tables | Credit notes, amendments or advances included on one side and not the other |
| Table 13 filled whenever supplies are reported | Table 13 left blank, which blocks filing |
The B2B value validation
The B2B tab of Table 12 is compared with the B2B values reported in the invoice-level tables, including 4A, 4B, 6B and 6C, B2B credit and debit notes in 9B, amendments in 9A and 9C, and the B2B rows of Tables 8 and 15. These checks were introduced in warning mode, so a mismatch has generally not stopped filing. It still matters: a Table 12 that does not agree with the rest of the return is a weak document if the HSN summary is ever relied on in an audit or the annual return.
Table 13: documents issued
Table 13 lists the serial ranges of the documents issued in the period: invoices, credit and debit notes, receipt vouchers, payment vouchers, refund vouchers and delivery challans, with the totals issued and cancelled. If any B2B or B2C supply is reported and Table 13 is blank, the portal shows an error and will not file the return. Pull the ranges from the billing system's document series, and record cancelled documents as cancelled rather than leaving gaps in the series.
A pre-filing routine
- Check the item master against the HSN dropdown each quarter, and whenever new items are added.
- Confirm the HSN digit level matches the client's aggregate turnover in the previous year.
- Generate Table 12 from the billing system with B2B and B2C separated at the source, not split by hand.
- Reconcile the B2B tab to the B2B invoice tables by tax head.
- Fill Table 13 from the document series, including cancelled documents.
- Once filed, keep each month's Table 12 so the annual HSN tables in GSTR-9 can be built from twelve clean summaries.
Checking Table 12 against the rest of the return, and building the annual HSN summary for GSTR-9, is easier with filed returns in a spreadsheet. GST Reco Pro converts GSTR-1 PDFs, including HSN and documents-issued data, into Excel in your browser.
Convert GSTR-1 PDFs to Excel →Related reading: using the monthly HSN summaries to split FY 2025-26 at the GST 2.0 rate change.
Read the GSTR-9 rate change guide →Frequently Asked Questions
Is Table 13 mandatory in GSTR-1?
Yes. From the May 2025 return period, Table 13 (documents issued) is mandatory in GSTR-1 and GSTR-1A. If supplies are reported and Table 13 is blank, the portal will not file the return.
Why does GSTR-1 Table 12 now have separate B2B and B2C tabs?
Under Phase III of HSN reporting, Table 12 was split so that B2B and B2C HSN summaries are reported separately. The portal then checks the B2B tab against the B2B values in the invoice-level tables of the return.
How many HSN digits are required in GSTR-1?
At least 4 digits for taxpayers with aggregate turnover up to ₹5 crore in the previous financial year, and at least 6 digits above ₹5 crore. HSN codes are now selected from a dropdown on the portal.
Will a Table 12 value mismatch stop me from filing GSTR-1?
The value validations between Table 12 and the other tables were introduced in warning mode, so a mismatch has generally not blocked filing. Table 13 being blank does block filing. Check current GSTN advisories, since warning-mode checks can become blocking.