Step-by-Step GSTR-3B Filing on the GST Portal in India

If you are registered under GST, filing GSTR-3B is one of your most critical monthly or quarterly responsibilities. Missing deadlines leads to late fees and interest charges, and continued non-filing can lead to suspension and cancellation of your GST registration.

This guide simplifies the filing process, covering due dates, late fees, ITC rules, and step-by-step filing for 2026.

How to Log In to the GST Portal

Before you can file GSTR-3B, you need to log in to the official GST portal. Here's how:

GST Portal Login Steps

1. Visit the GST portal: Go to www.gst.gov.in (the official Goods and Services Tax portal for India)
2. Click "Login" in the top-right corner
3. Enter your credentials:
   • Username: The user ID you created on the portal (not your GSTIN)
   • Password: Your GST portal password
   • Captcha: Type the characters shown on screen
4. Two-Factor Authentication: Enter the OTP sent to your registered mobile number or email
5. Dashboard Access: Once logged in, you reach the GST dashboard where you can file GSTR-3B and GSTR-1 and manage your compliance

First-Time GST Portal Login or Password Reset

• After registration is approved, use the "First time login" link on the login page with the provisional ID or GSTIN and the temporary password sent to your email, then create your own username and password
• New registration applications are made through Services > Registration > New Registration on the portal
• If you forgot your password, click "Forgot Password" and verify via OTP
• For portal issues, use the GST helpdesk or the grievance redressal portal linked from gst.gov.in

Key GST Portal Features for GSTR-3B Filing

• Secure Login: 2FA authentication protects your GST account
• Offline Tools: Download the returns offline tool to prepare GSTR-1 data before uploading
• Form Pre-fill: GSTR-3B liability tables auto-populate from your GSTR-1 (and GSTR-1A), and ITC tables auto-populate from GSTR-2B
• Real-time Filing Status: Track your GSTR-3B filing status and download the filed return and ARN

What is GSTR-3B?

GSTR-3B is a self-declared summary return. Unlike GSTR-1, which captures invoice-level sales details, GSTR-3B is where you finalise your numbers and pay the tax due to the government.

In this return, you declare:

• Outward Supplies: Total sales and tax payable.
• Inward Supplies: Purchases subject to Reverse Charge.
• Input Tax Credit (ITC): Tax paid on business purchases you are claiming, and reversals.
• Tax Payment: The net amount paid after offsetting liability with credits.

Who is Required to File?

GSTR-3B filing is mandatory for all normal taxpayers and casual taxable persons. Composition taxpayers (CMP-08 and GSTR-4), input service distributors, non-resident taxable persons and TDS/TCS deductors file other returns instead.

Note on Inactive Businesses: Even if you had zero business activity during the period, you must file a NIL return to avoid late fees. See our nil GST return filing guide.

GSTR-3B Due Dates (2026 Rules)

Monthly Filers

For taxpayers with aggregate annual turnover above Rs. 5 crore in the preceding financial year, or those who have not opted for QRMP:

• Due Date: 20th of the following month.
• Example: Your March 2026 return is due by April 20, 2026.
• Every GSTR-1, GSTR-3B and GSTR-9 date for the year is in our GST return due dates calendar for FY 2025-26.

Quarterly Filers (QRMP Scheme)

Businesses with aggregate turnover up to Rs. 5 crore can opt to file quarterly but must pay tax for the first two months of each quarter using form PMT-06 by the 25th of the following month.

• Category A states (including Telangana, Andhra Pradesh, Karnataka, Tamil Nadu and Maharashtra): 22nd of the month following the quarter
• Category B states (including Delhi, Uttar Pradesh, Bihar, Punjab and the North-Eastern states): 24th of the month following the quarter

Three-Year Time Bar

From the July 2025 tax period, the portal does not accept a GSTR-3B after three years from its due date (Section 39(11) of the CGST Act, inserted by the Finance Act 2023). Old pending returns cannot be filed once they cross this limit.

Penalties and Interest

Late Fees (Section 47, Notification 19/2021-Central Tax)

Late fee is not payable from the credit ledger; it must be paid in cash.

Interest on Late Payment

If you fail to pay the tax liability by the due date:

• Rate: 18% per annum under Section 50(1), counted for each day of delay.
• Calculation: Interest is calculated on the portion of tax paid in cash (net cash liability), not on tax set off from ITC.
• Auto-calculation: From the January 2026 tax period, the portal computes this interest in Table 5.1 of GSTR-3B. You can increase the figure but not reduce it.
• ITC wrongly availed and utilised attracts interest at 18% under Section 50(3).

Example: Net cash tax of Rs. 1,00,000 for a monthly return due 20 April 2026, paid and filed on 5 May 2026 (15 days late): interest = 1,00,000 x 18% x 15 / 365 = Rs. 740 (rounded), plus late fee of Rs. 50 x 15 = Rs. 750.

Input Tax Credit (ITC) Rules

ITC is a powerful tool to reduce your tax burden, provided it is used correctly.

Key Requirements (Section 16)

• You must possess a valid tax invoice or debit note and have received the goods or services.
• The supplier must have reported the invoice in GSTR-1 so that it appears in your GSTR-2B.
• The supplier must have paid the tax and filed its return.
• ITC for a financial year must be claimed by 30 November of the following year or the date of filing the annual return, whichever is earlier (Section 16(4)).
• Utilisation must follow a strict order (Section 49 and Rule 88A):
  1. IGST Credit: Used first, against IGST, then against CGST or SGST in any order.
  2. CGST Credit: Offsets CGST, then IGST (not SGST).
  3. SGST Credit: Offsets SGST, then IGST (not CGST).

Step-by-Step Filing Process

1. Portal Login: Visit the official GST portal and log in.
2. Dashboard: Go to Services > Returns > Returns Dashboard and select the financial year and period.
3. Review Auto-populated Data: Check the liability pulled from GSTR-1/GSTR-1A and the ITC pulled from GSTR-2B against your books. Take any IMS action (optional; invoices with no action are deemed accepted) before filing, since GSTR-2B can be recomputed only until GSTR-3B is filed.
4. Confirm Liability: Since the July 2025 tax period, the Table 3 liability auto-filled from GSTR-1/1A cannot be edited in GSTR-3B. Correct errors by filing GSTR-1A before GSTR-3B, or through a later GSTR-1.
5. Offset & Payment: Use your electronic credit ledger, then pay any balance in cash through net banking, NEFT/RTGS, over the counter or other modes offered on the portal.
6. Verification: File using EVC (OTP) or Digital Signature Certificate (DSC). DSC is compulsory for companies.

Practical Tips and Common Mistakes

Tips for Efficiency

• Reconcile Monthly: Match books with GSTR-2B to ensure no ITC is missed or overclaimed. See our GSTR-2A vs GSTR-2B reconciliation guide.
• File Early: Avoid the 20th-day rush to prevent portal downtime.
• Use SMS for NIL: File a NIL return via SMS from your registered mobile number in the format NIL 3B GSTIN period.

Mistakes to Avoid

• Claiming ITC without a valid invoice or where the supplier hasn't reported the invoice.
• Forgetting to file a return for zero-activity months.
• Incorrectly entering values in IGST/CGST/SGST columns.
• Filing GSTR-3B before correcting GSTR-1 errors through GSTR-1A, now that the liability table is locked.

Related reading

For how outward liability in GSTR-3B is now locked to GSTR-1 and how to fix differences, see our GSTR-1 vs GSTR-3B mismatch reconciliation guide. If you would rather hand over the monthly reconciliation and filing, see Tax Garden's GST filing services.

Frequently Asked Questions

Do I have to file GSTR-3B if my business had no sales or purchases?

Yes. Every normal taxpayer must file GSTR-3B for each period even with zero activity, as a nil return. You can file it on the portal or by SMS from the registered mobile number in the format NIL 3B GSTIN period. A late nil return attracts a fee of Rs 20 per day, capped at Rs 500, and six months of non-filing can lead to cancellation of registration.

What is the difference between GSTR-1 and GSTR-3B?

GSTR-1 is an invoice-level statement of your outward supplies, due on the 11th of the next month for monthly filers. GSTR-3B is the summary return where you declare total outward supplies, reverse charge purchases and eligible ITC, and actually pay the net tax, due on the 20th. Your GSTR-1 data auto-populates the liability tables in GSTR-3B.

Which GSTR-3B due date applies to Telangana businesses under QRMP?

Telangana is in the Category A group, so quarterly GSTR-3B under the QRMP scheme is due on the 22nd of the month after the quarter. For the first two months of each quarter, tax is paid through PMT-06 by the 25th of the next month. Monthly filers, including all businesses with turnover above Rs 5 crore, file by the 20th.

Can I use CGST credit to pay SGST liability in GSTR-3B?

No. CGST credit can be used only against CGST and then IGST, and SGST credit only against SGST and then IGST. Cross-utilisation between CGST and SGST is not allowed. IGST credit must be used first, against IGST and then against CGST or SGST in any order, before CGST or SGST credit is touched.

How is interest calculated if I pay GSTR-3B tax late?

Interest is charged at 18% per annum under Section 50(1) of the CGST Act on the tax paid in cash after the due date, counted day by day until payment. Tax discharged through input tax credit does not attract this interest when the return is filed. The portal now auto-populates this interest in Table 5.1 of the next GSTR-3B.

Can GSTR-3B be revised after filing?

No. Once filed, GSTR-3B cannot be revised. Any missed sales, excess ITC or other errors must be corrected in the GSTR-3B of a later month, before 30 November following the end of the financial year, or reported in the annual return. Checking auto-populated figures against your books and GSTR-2B before submitting is the only way to avoid carry-forward corrections.