Understanding the Current Design of the GST System and GSTR-1 Transactions

Table 12 of GSTR-1: B2B vs. B2C Validation (July 2025)

If you're in the thick of GST compliance this filing season, Table 12 of GSTR-1 might already be giving you a fair bit to think about. And with the July 2025 update in effect, it’s become more important than ever to understand how the government is treating B2B vs. B2C HSN reporting—because the rules are now clearly different for the two.

B2B Transactions: No Room for Error

Let’s start with B2B. If you’re raising invoices to registered taxpayers, then strict validation rules now apply.

HSN Reporting is Mandatory:

• If your annual turnover is ₹5 crore or less, you must enter 4-digit HSN codes in Table 12.
• If your turnover exceeds ₹5 crore, then a 6-digit HSN is compulsory.

No exceptions here.

HSN Entry Is Drop-Down Only:

There’s no manual typing allowed anymore. The system has shut off that option. You now need to choose from a drop-down list of HSN/SAC codes. Once you do, the official “Description” auto-fills—so there’s no second guessing.

System-Wide Cross-Validation:

The portal doesn’t just take your word for it. It now checks what you’ve reported in Table 12 against multiple other tables—specifically, Tables 4A, 4B, 6B, 6C, 8 (registered), 9A, 9B, 9C, 15, and 15A. If you’ve reported B2B supplies elsewhere, Table 12 cannot be left blank. The system will flag that.

Enforcement:

Right now, it’s still in “warning mode.” So even if you mess up or skip something, the portal will allow filing—but it’ll throw a compliance alert. Think of it as a nudge. But don’t get too comfortable—these nudges might become non-negotiable in the future.

B2C Transactions: More Breathing Room

Now, if your invoices go to unregistered customers (B2C), it’s a different story.

HSN in B2C is NOT Mandatory:

You can leave the B2C section in Table 12 blank if you want. Yes, the system might show a warning—but there’s no validation barrier, and your return will still go through.

Validation Is Advisory:

Let’s say you’ve reported B2C data in Tables 5A, 6A, 7A, 7B, 8 (unregistered), 9A (exports/B2CL), 9B, 9C, 10, 15, or 15A, but left Table 12B empty. The system will raise an eyebrow—but just that. These alerts are informational only. No enforcement, no submission block.

System Enhancements and Filing Experience

To make life easier, the portal has rolled out a few usability upgrades alongside these validations:

Split View & Downloadable Help:

• Table 12 is now clearly divided into “B2B Supplies” and “B2C Supplies”, so you’re not mixing up one with the other.
• You can download an Excel file of all valid HSN/SAC codes, which helps when you need to cross-check.

Product Master Search:

If you’ve created a product master list, you can now search using your own product names. When selected, it can auto-fill HSN, UQC, and quantity fields—though this feature is completely optional.

Table 13: Now Compulsory for Everyone

This one’s important.

Since May 2025, Table 13—which covers the summary of documents issued—is now a mandatory field. If you’ve reported any B2B or B2C transactions elsewhere in GSTR-1 or GSTR-1A, skipping Table 13 will block your filing. There’s no override.

Quick Summary

Here’s how it all stacks up:

• B2B HSN summary (Table 12A/B2B): Mandatory. Strictly validated. Cannot be blank if B2B data is declared elsewhere.
• B2C HSN summary (Table 12B/B2C): Optional. Can be left blank. Warnings are advisory.
• System: Real-time validations, clean UI, auto-fill features, but enforces only what’s required by law.
• Table 13: Compulsory for anyone reporting B2B/B2C transactions.

Practical Takeaway

If your business involves B2B, precision is key. Stay compliant with HSN codes, use the drop-down menus, and don’t leave Table 12 empty if B2B data appears elsewhere.

For B2C, you have more leeway—but don’t take it for granted. Advisory alerts could become binding tomorrow.

And whatever you do, don’t skip Table 13—because that’s one field the portal simply won’t let you ignore anymore.