# GSTR-1 and GSTR-3B: the difference and why they must match

> GSTR-1 lists your sales invoice by invoice and is due on the 11th. GSTR-3B is the summary return in which you pay the tax, after input tax credit, and is due on the 20th. As of October 2026 the sales tax in GSTR-3B is filled from GSTR-1 and cannot be edited, so GSTR-1 must be right first.

## The two returns side by side

| | GSTR-1 | GSTR-3B |
|---|---|---|
| What it is | A statement of your sales | A summary return with payment |
| Detail | Invoice by invoice for business customers; summary for consumers | Totals only |
| Covers | Sales, credit and debit notes, exports, advances, HSN summary | Tax on sales, input tax credit, tax under reverse charge, net tax paid |
| Payment | None | Tax paid in cash or by credit |
| Due, monthly filers | 11th of the next month | 20th of the next month |
| Due, QRMP filers | 13th after the quarter | 22nd or 24th after the quarter |
| Who uses it | Your customers, whose GSTR-2B is built from it | The government, as your self-assessed tax |

All dates for the year are on the [GST due dates](/tools/gst-due-dates) page.

## How they connect

Think of the month as a chain:

1. You issue invoices and report them in [GSTR-1](/glossary/gstr-1) by the 11th.
2. Your suppliers do the same, and their invoices reach your Invoice Management System and then
   your [GSTR-2B](/glossary/gstr-2b) on the 14th.
3. The portal prepares your [GSTR-3B](/glossary/gstr-3b): tax on sales from your GSTR-1, and
   input tax credit from your GSTR-2B.
4. You check it, pay the balance and file by the 20th.

## What changed, as of October 2026

- **The sales side of GSTR-3B is locked.** From the July 2025 tax period, the tax liability filled
  in from GSTR-1, GSTR-1A and the IFF cannot be edited in GSTR-3B.
- **Corrections go through [GSTR-1A](/glossary/gstr-1a).** After filing GSTR-1 and before filing
  GSTR-3B, you can add a missed invoice or correct one for the same period.
- **Credit is decided in the [IMS](/glossary/ims).** You accept, reject or keep pending each
  supplier invoice, and what you accept becomes your GSTR-2B.
- **Old returns close after three years.** A return cannot be filed more than three years after
  its due date.

The practical meaning is simple. A mistake in GSTR-1 is now a mistake in the tax you pay, so the
checking has to happen before the 11th, not on the 20th.

## A check before you file GSTR-1

- Every invoice of the month is issued, not left as a draft.
- Credit notes for returns and rate differences are raised and dated in the month.
- Each business customer's GSTIN is correct. Try the [GSTIN checker](/tools/gstin-checker).
- The place of supply is right, so CGST and SGST or IGST is right.
- HSN codes have the number of digits your turnover requires.
- The total agrees with the sales in your books for the month.

## When the two still differ

Compare three numbers for the period: taxable sales in your books, in GSTR-1 and in GSTR-3B. If
books and GSTR-1 differ, a document was added or changed after filing. If GSTR-1 and GSTR-3B differ
for an older period, the difference was usually adjusted by hand in a later month; write down where,
because your annual return will ask.

## Questions

### Which is filed first, GSTR-1 or GSTR-3B?

GSTR-1. The portal does not let you file GSTR-3B for a period until GSTR-1 for that period is filed, because the tax on your sales in GSTR-3B is taken from it.

### Do I pay tax in GSTR-1?

No. GSTR-1 is a statement of your sales with no payment. The tax is paid when you file GSTR-3B, after setting off your input tax credit.

### What if I find a mistake in GSTR-1 after filing it?

If you have not yet filed GSTR-3B for that period, correct it through GSTR-1A. If you have, show the amendment in the next period's GSTR-1.

### Why do my GSTR-1 and GSTR-3B not match?

The usual causes are invoices added to the books after GSTR-1 was filed, credit notes reported in one and not the other, advances, and amendments of earlier periods. Since the July 2025 period the portal fills GSTR-3B from GSTR-1, which removes most of these differences.

### Do quarterly filers file both?

Yes. Under the QRMP scheme both are filed once a quarter, GSTR-1 by the 13th and GSTR-3B by the 22nd or 24th of the month after the quarter, with tax paid monthly through PMT-06.

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Source: https://www.easedesk.com/blog/gstr-1-vs-gstr-3b-difference · Updated 2026-10-02 · EaseDesk