GST Return Filing Guide: GSTR-1, GSTR-3B, GSTR-9, Due Dates, Late Fees and QRMP Explained

If you are registered under GST, you must file returns regularly, even in months with no sales. Missing them brings late fees, interest and eventually cancellation of registration. This guide explains the common returns, who files what, how input tax credit works and how to stay compliant without stress.

The main returns

Due dates

Typical due dates are the 11th of the following month for GSTR-1 and around the 20th for GSTR-3B for monthly filers, with later dates for QRMP filers and some states. The government extends dates from time to time, so check the GST portal. The annual return is generally due by 31 December of the following financial year, unless extended.

What is the QRMP scheme?

The Quarterly Return Monthly Payment scheme is for taxpayers with an aggregate turnover up to ₹5 crore. You file GSTR-1 and GSTR-3B quarterly and pay tax each month using a challan, and use the invoice furnishing facility (IFF) to upload B2B invoices monthly if you want your buyers to claim credit. It reduces filings from 24 to 8 a year for returns of this type.

Input tax credit (ITC)

You can reduce your tax payable by the GST paid on business purchases, if the supplier has filed their return and the credit appears in your GSTR-2B statement. Keep these habits:

• Match your purchase register with GSTR-2B every month.
• Claim ITC only on eligible items. Some, such as personal use goods and some motor vehicle expenses, are blocked.
• Follow up with suppliers who have not filed.
• Reverse ITC where required, for example when you do not pay a supplier within 180 days.

Read more in our ITC guide and use the GST calculator for tax amounts.

Late fees and interest

A late fee applies per day for each late return, with a lower daily rate for nil returns and an overall cap that depends on turnover. Interest at 18% a year applies on tax paid late. Use the GST late fee calculator to estimate. Filing even a nil return on time is far cheaper than ignoring the deadline.

Nil returns

If you have no sales or purchases in a period, you still must file a nil return, which can be done quickly by SMS or the portal. Not filing for a continuous period, for example six months for regular taxpayers, can lead to cancellation of your registration.

Monthly routine for a small business

1. Record all sales invoices and credit notes.
2. Record purchase bills and check GSTR-2B.
3. File GSTR-1 by the due date.
4. Compute tax liability, net of eligible ITC.
5. Pay tax via the portal and file GSTR-3B.
6. Download acknowledgements and keep records for at least six years.

Common mistakes

• Using the wrong HSN or SAC code, or a wrong tax rate.
• Claiming ITC that does not appear in GSTR-2B.
• Mismatch between GSTR-1 and GSTR-3B, leading to notices.
• Missing amendments to earlier invoices.
• Not keeping the GSTIN, login and mobile number updated. Verify numbers with the GST number validator.

When to get professional help

If you deal across states, import or export, run multiple branches or face a notice, a GST practitioner or chartered accountant is worth the fee. Also read our GST calculator guide.

Due dates, thresholds and fee structures are changed by notification. Confirm them on the official GST portal.

Reconciliation tips that prevent notices

Compare your GSTR-1 sales with your GSTR-3B turnover every month, and explain any differences in a note to your accountant. Match your books with the portal's GSTR-2B and track unmatched supplier invoices in a separate list. Review credit notes and debit notes, since errors there often cause mismatches. Before the annual return, reconcile the year's sales, purchases and tax paid with your financial statements. Setting calendar reminders a week before each due date and keeping a folder of acknowledgements for each return gives you an audit trail if a notice arrives.

Frequently asked questions

What is GSTR-3B?

A summary return where you report sales, claim input tax credit and pay tax.

What is the QRMP scheme?

A scheme for small taxpayers to file returns quarterly while paying tax monthly.

Do I need to file if I had no sales?

Yes, file a nil return on time.

What is the late fee?

A per-day fee with a cap, plus 18% interest on late tax payment.

How do I claim input tax credit?

Claim it in GSTR-3B for eligible purchases that appear in your GSTR-2B.

Who must file the annual return?

Regular taxpayers above the turnover threshold set by the government.

Last reviewed 8 November 2026. Rates, limits and rules change, so confirm figures with the official source before you act.