GSTR-1 vs GSTR-3B Mismatch Checker
The most common trigger for a GST notice is these two returns not agreeing. Check yours before you file — not after the department does.
From your GSTR-1
From your GSTR-3B (Table 3.1)
Get GSTR-1 right the first time
GSTWali builds your GSTR-1 straight from your marketplace report and shows you the totals reconcile before you download — so there's nothing to mismatch later.
Generate GSTR-1 free →Why this matters
GSTR-1 reports what you sold. GSTR-3B is the summary on which you actually pay. The GST system compares the two automatically, and a gap suggests you either under-reported sales or under-paid tax. That is what generates a DRC-01B liability notice or an ASMT-10 scrutiny notice.
Differences that are perfectly legitimate
A mismatch is not automatically a mistake. Common genuine reasons:
- Timing — an invoice reported in GSTR-1 for one month but accounted in 3B in another
- Amendments — corrections made in a later period's GSTR-1
- Credit notes — reported in a different month to the original invoice
- Advances — tax paid on advances appears in 3B before the supply appears in GSTR-1
- RCM supplies — reported in 3B but not as outward supply in GSTR-1
The department's concern is not that the numbers are always identical — it is whether you can explain the difference. Keep a short note each month recording why.
If you find a mismatch before filing
- Recheck which period each figure belongs to
- Confirm returns and credit notes are counted once, in the right month
- Check that interstate and intrastate tax has been split the same way in both returns
- Correct the return you have not yet filed, rather than filing and amending later
Please note: this tool compares figures you enter. It cannot access the GST portal or verify what was actually filed. It is a pre-filing sanity check, not tax advice, and small rounding differences of a few rupees are normal. For a formal reconciliation or a notice you have already received, speak to a qualified practitioner. Verified July 2026.