Last updated: 21 July 2026. Every GSTR-1 asks for an HSN-wise summary of what you supplied — and the single most common question is how many digits of the HSN code you actually have to enter. The answer is not the same for everyone. It is decided by your aggregate annual turnover (AATO) in the preceding financial year: four digits up to ₹5 crore, six digits above it. On top of that, the way Table 12 itself works changed with the Phase-3 rollout, and manual typing of HSN codes is gone. Here is the full picture.
Applicability Note: This guide is based on GST provisions applicable as of 21 July 2026. HSN reporting rules and Table 12 behaviour are changed through CBIC notifications and GSTN advisories. Always verify the current position on gst.gov.in or with a GST professional before filing.
Who Should Care?
- Every regular GSTR-1 filer — Table 12 is a mandatory part of the return, and the digit requirement applies whether you file monthly or quarterly under QRMP.
- Businesses near the ₹5 crore line, where crossing it moves you from 4-digit to 6-digit reporting — and who should be checking their AATO this month.
- Anyone who last filed GSTR-1 by typing HSN codes into Table 12 — that box is now a dropdown.
- Accountants reconciling Table 12 totals against the rest of the return and seeing new mismatch warnings.
1. The Core Rule: Your Turnover Decides the Digits
Under Notification No. 78/2020-Central Tax dated 15 October 2020, the minimum number of HSN digits you must report is tied to your aggregate annual turnover in the preceding financial year:
| Aggregate turnover (preceding FY) | Minimum HSN digits in Table 12 | Live since |
|---|---|---|
| Up to ₹5 crore | 4 digits | 1 November 2022 (Phase 2) |
| More than ₹5 crore | 6 digits | 1 April 2021 (Phase 1) |
"Minimum" matters: nothing stops a 4-digit filer from reporting a fuller 6- or 8-digit code, and for many products the correct classification only becomes clear at 6 or 8 digits. The rule sets a floor, not a ceiling. What it does not allow is reporting fewer digits than your bracket requires — a ₹5-crore-plus business entering a 4-digit code will be stopped.
2. It's Your Preceding-Year Turnover — and This Is the Month to Check It
The bracket for the whole of FY 2026-27 is fixed by your AATO for FY 2025-26, not by how you are trading right now. So the figure that decides whether you report 4 or 6 digits this year is a number that was locked in when last year closed.
That number is not beyond correction. The FY 2025-26 AATO amendment window on the GST portal is open from 1 to 31 July 2026. If the auto-computed turnover on your dashboard is wrong — and a business sitting just either side of ₹5 crore has a real reason to care — this is the month to get it fixed, because the same AATO figure also drives your e-invoicing and QRMP eligibility. Miss the window and you carry the portal's number, and its HSN bracket, for the year. Confirm your AATO on the portal before you rely on a 4-digit code.
3. What Changed in Table 12: The Phase-3 Rollout
From the April 2025 tax period (returns filed in May 2025), GSTN rolled out Phase-3 changes to Table 12 of GSTR-1 and GSTR-1A. Three things are different from how the table used to work:
Manual entry is gone — HSN is now a dropdown
You can no longer type an HSN code straight into Table 12. You select it from a predefined dropdown, and the description auto-fills. This kills the old problem of invalid or mistyped codes, but it also means a code that isn't on the master list can't be entered — if yours is missing, that is a portal query, not something you can force through by typing.
Table 12 is split into B2B and B2C
The single HSN summary has been bifurcated into two tabs — one for B2B supplies and one for B2C supplies. You report the HSN-wise summary separately under each, rather than in one combined block.
Value validations now cross-check your totals
The portal now compares the values in Table 12 against the corresponding figures elsewhere in the return — the B2B HSN summary against your B2B supply tables, the B2C summary against the B2C tables. If they don't tie out, you get an alert.
The validations are warnings, not blockers. Per the GSTN advisory dated 22 January 2025 and later clarifications, these Table 12 value-mismatch checks run in warning mode only. A mismatch shows an alert, but you can still file GSTR-1/1A. Treat the warning as a prompt to reconcile — an unexplained gap between Table 12 and the rest of the return is exactly the kind of thing that later invites a query.
4. B2B Is Mandatory; B2C Is Optional Below ₹5 Crore
The two tabs are not treated the same:
- B2B — mandatory for everyone. HSN reporting for B2B supplies has no turnover exemption. Whether you are a ₹40 lakh business or a ₹40 crore one, your B2B HSN summary must be filled (at your bracket's digit count).
- B2C — optional up to ₹5 crore. Per subsequent GSTN clarifications after the 22 January 2025 Phase-3 rollout, taxpayers with AATO up to ₹5 crore may leave the B2C HSN summary optional. The reasoning is practical: small retailers selling to end consumers rarely track item-level HSN at the counter. Above ₹5 crore, report B2C as well.
5. Don't Forget the Invoice Itself
Table 12 is the return side, but the same Notification No. 78/2020-Central Tax also requires the HSN/SAC to appear on the tax invoice — 4 or 6 digits on the same turnover logic. And if you are in the e-invoicing net, your e-invoice must carry at least a 6-digit HSN. So a business above ₹5 crore is on 6 digits across the board: invoice, e-invoice, and Table 12. Keeping the code consistent between your invoice and your GSTR-1 is what makes the new value validations pass quietly.
Key Takeaways
- HSN digits in GSTR-1 Table 12 follow your preceding-year AATO: 4 digits up to ₹5 crore, 6 digits above — per Notification No. 78/2020-Central Tax dated 15 October 2020.
- The number that fixes your bracket is your FY 2025-26 turnover; the amendment window to correct it is open 1–31 July 2026.
- Phase 3 (live since the April 2025 period) replaced manual HSN entry with a dropdown, split Table 12 into B2B and B2C, and added value-mismatch checks.
- Those checks are warnings, not blockers — you can still file, but reconcile the gap.
- B2B HSN is mandatory for all; B2C is optional for filers up to ₹5 crore.
- The HSN also belongs on the invoice, and e-invoices need at least 6 digits.
Frequently Asked Questions
How many digits of HSN do I report in GSTR-1?
It depends on your aggregate turnover in the preceding financial year: 4 digits if it was up to ₹5 crore, 6 digits if it was more than ₹5 crore. This is set by Notification No. 78/2020-Central Tax dated 15 October 2020 and reported in Table 12 of GSTR-1.
Which year's turnover decides my HSN digit requirement?
Your preceding financial year's aggregate turnover. For returns in FY 2026-27, that is your FY 2025-26 AATO. The GST portal's AATO amendment window for FY 2025-26 is open 1–31 July 2026 if the auto-computed figure needs correcting.
Why can't I type the HSN code in Table 12 anymore?
Since the Phase-3 rollout (April 2025 tax period), manual entry was replaced by a dropdown. You select the HSN from a predefined list and the description auto-fills. If your code isn't in the list, raise it on the GST portal — it can't be entered manually.
The portal shows a mismatch warning on Table 12 — can I still file?
Yes. The Table 12 value validations run in warning mode only, so a mismatch does not block filing of GSTR-1 or GSTR-1A. But you should reconcile the difference between your Table 12 HSN summary and the corresponding supply tables before you file, since an unexplained gap can attract a later query.
Do I have to report HSN for B2C sales?
If your turnover is up to ₹5 crore, the B2C HSN summary is optional. B2B HSN reporting is mandatory for everyone regardless of turnover. Above ₹5 crore, report both B2B and B2C.
Disclaimer: This article is for informational purposes only and does not constitute professional tax advice. GST rules are subject to frequent changes through notifications and circulars. Please consult a qualified tax professional or verify the current provisions on the official GST portal (gst.gov.in) before making any compliance decisions.
Not sure which HSN bracket you fall in, or seeing Table 12 mismatch warnings you can't explain? Our GST experts can help → gstconsultancy.com