Before filing your monthly or quarterly GST returns, verifying your sales data is a priority. An incorrect GSTR-1 creates input tax credit mismatches for your buyers and can trigger notices for your own business.
What goes into GSTR-1
The form contains details of outward supplies of goods and services. Taxpayers can prepare these details using the offline utility downloaded from the portal. Taxpayers registered under the Composition Scheme do not file this form.
Missing the deadline: Filing late affects your buyers because your invoices will not appear in their GSTR-2B on time, blocking their ITC claims.
Due dates and filing frequency
The due date depends on your filing frequency:
- Monthly filers: The 11th day of the succeeding month.
- Quarterly filers: The 13th day of the month succeeding the end of the quarter.
How to amend errors in GSTR-1
You can modify or delete invoices any number of times until you submit the form. If you discover a mistake after filing, you can correct it in a subsequent month or use Form GSTR-1A. Form GSTR-1A allows you to amend a supply record in the same month after filing GSTR-1 and before filing GSTR-3B.
There is a strict time limit for past periods. As per the GSTN GSTR-1 FAQ, rectification of an error or omission for invoices of the previous financial year is not allowed after the 30th of November of the following financial year.
Worked example
Suppose you filed an invoice with the wrong taxable value. You can use GSTR-1A to fix it before your buyer loses their credit.
| Invoice | Declared value | Actual value | Action required |
|---|---|---|---|
| INV-101 | ₹15,000 | ₹1,50,000 | Amend in GSTR-1A |
| INV-102 | ₹45,000 | ₹45,000 | None |
Frequently asked questions
What is the time limit to rectify errors in GSTR-1?
In Form GSTR-1, rectification of an error or omission for invoices of the previous financial year is not allowed after the 30th of November of the following financial year.
Check your own GSTR-2B
Your GSTR-2B and purchase register files are read in your browser and never uploaded to any server. See exactly which invoices match and which need amendments.
Last checked: 10 October 2026. Sources: GSTN GSTR-1 User Manual, GSTN GSTR-1A FAQ. Read our guides on ineligible ITC lists and Tally Prime reconciliation.