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A small business owner thinks GSTR-1 and GSTR-3B are two versions of the same return and types sales figures into GSTR-3B that differ from the invoices already reported.
GSTR-1 reports sales invoice by invoice and feeds customers' credit; GSTR-3B declares summary tax, claims credit and pays. The system compares them and flags short payment through DRC-01B.
File GSTR-1 first by the 11th; let GSTR-3B Table 3.1 pre-fill from it; reconcile any difference before the 20th.
Tax in GSTR-3B that agrees with GSTR-1 each month, with no DRC-01B intimations and no unpaid tax.
GSTR-1 is your sales return. It lists every sale invoice, one by one, and your customers’ credit depends on it. GSTR-3B is your monthly summary return. In it you declare the total tax on your sales, claim your own input tax credit (ITC), and pay the balance. They do different jobs, but the tax in both must agree.
Side by side
| GSTR-1 | GSTR-3B | |
|---|---|---|
| Purpose | Report outward supplies | Declare tax, claim ITC, pay |
| Level of detail | Invoice by invoice for B2B; summaries for B2C | Totals only |
| Who sees it | Your customers, through their GSTR-2B | Only you and the department |
| Due date (monthly filer) | 11th of the next month | 20th of the next month |
| Due date (QRMP filer) | 13th after the quarter | 22nd or 24th after the quarter |
| What it feeds | Customers’ GSTR-2B; your GSTR-3B Table 3.1 | Your cash and credit ledgers |
| Section of the CGST Act, 2017 | Section 37 | Section 39 |
| Late filing cost | Late fee; customers’ credit delayed | Late fee plus interest at 18% a year on unpaid tax |
Must the tax in GSTR-1 and GSTR-3B be the same?
Yes, for the same period, after allowed adjustments. The portal pre-fills GSTR-3B Table 3.1 from your GSTR-1, and it compares the two after you file. Under Rule 88C of the CGST Rules, if the tax in GSTR-3B is lower than in GSTR-1 by more than the prescribed amount, you receive an intimation in Form DRC-01B. You must then pay the difference with interest, or explain it. Until you respond, you may be blocked from filing your next GSTR-1.
Some differences are genuine: an invoice wrongly reported in GSTR-1 and corrected later, or an amendment through GSTR-1A. But each one needs a reason.
Worked example: a ₹16,200 short payment
A Nagpur supplier reports ₹5,90,000 of sales in GSTR-1 for the month. When filling GSTR-3B, the accountant overwrites the pre-filled figure with ₹5,00,000 taken from an old sales report.
- Tax per GSTR-1: ₹5,90,000 × 18% = ₹1,06,200
- Tax per GSTR-3B: ₹5,00,000 × 18% = ₹90,000
- Short paid: ₹1,06,200 minus ₹90,000 = ₹16,200
The customers are fine; they see all ₹5,90,000 of invoices in their GSTR-2B and claim credit. But the supplier has under-paid ₹16,200. Interest at 18% a year runs from the 21st until it is paid. If the gap is large enough, a DRC-01B intimation follows.
The fix: pay the ₹16,200 in the next GSTR-3B (or through DRC-03) with interest, and stop overwriting the pre-filled Table 3.1 without a documented reason.
Which return do your customers’ credits depend on?
GSTR-1. Your customers can claim credit only when your invoice appears in their GSTR-2B, and their GSTR-2B is built from your GSTR-1. If you file GSTR-1 late, or with the wrong customer GSTIN, they lose or delay credit, and they will call you. Your GSTR-3B matters to them too: under Section 16(2)(c), their credit is valid only if you actually paid the tax, which you do in GSTR-3B.
A simple monthly order
- Finish the sales register and credit notes.
- File GSTR-1 by the 11th.
- Wait for GSTR-2B on the 14th; review your own purchase credit.
- Check that GSTR-3B Table 3.1 matches GSTR-1.
- File GSTR-3B and pay by the 20th.
What to read next
For the deeper monthly match between the two returns, read GSTR-1 vs GSTR-3B reconciliation. If you have already received an intimation, see what to do when you get a DRC-01B notice. For the buyer’s side of the same invoice, see how one invoice travels from GSTR-1 to GSTR-2B and GSTR-3B.
GST outward reconciliation (GSTR-1 and GSTR-3B) leads the TransactIG GST roadmap; inward matching (GSTR-2B, ITC, IMS) is on the roadmap. See the GST reconciliation page.