How to File GSTR-3B: Step-by-Step Guide with Due Dates (2025–26)

GSTR-3B is the monthly or quarterly summary return where you declare your total sales, claim Input Tax Credit, and pay the net GST owed to the government. Unlike GSTR-1, it doesn't require invoice-level detail — but it does require you to get every consolidated number exactly right, because once filed, it <strong>cannot be revised</strong>.

This guide walks you through what GSTR-3B is, who must file it, due dates for FY 2025–26, and a complete step-by-step filing walkthrough — including the landmark 2025 change that makes GSTR-1 accuracy more critical than ever.

What Is GSTR-3B?

GSTR-3B is a consolidated summary return filed by all regular GST taxpayers. It reports:

• Total value of outward supplies (sales) — now auto-populated from GSTR-1
• Eligible Input Tax Credit claimed
• Reverse Charge Mechanism (RCM) liability
• Net tax payable and payment details

Unlike GSTR-1 which is a ledger of individual invoices, GSTR-3B deals only in totals. It is the return through which you actually pay your GST liability for the period.

Who Must File GSTR-3B?

Must file GSTR-3B:

• All regular registered taxpayers
• SEZ units and SEZ developers
• Casual taxable persons

Exempt from GSTR-3B:

• Composition scheme taxpayers (file CMP-08 instead)
• Input Service Distributors
• Non-resident taxable persons
• TDS deductors and TCS collectors

GSTR-3B Due Dates for FY 2025–26

Monthly Filers (Turnover > ₹5 Crore)

Due on the 20th of the following month for all states.

QRMP Quarterly Filers (Turnover ≤ ₹5 Crore)

Due dates vary by state group:

PMT-06 — Monthly Tax Payment Under QRMP

Even though QRMP filers submit GSTR-3B quarterly, they must pay tax monthly via PMT-06 challan — due the 25th of each month for months 1 and 2 of the quarter.

The 2025 Change That Changes Everything: GSTR-3B Is Now Partially Locked

This is the single most important update for FY 2025–26 — and most guides either miss it or bury it.

What changed:

• From July 2025: Table 3 (outward supply liability — your total GST on sales) is auto-populated from GSTR-1/1A/IFF and cannot be manually edited in GSTR-3B.
• From November 2025: Table 3.2 (inter-state supplies to unregistered persons, composition dealers, and UIN holders) is also locked.

What this means in practice:

What Should You Prepare Before Filing GSTR-3B?

• GSTR-1 filed and submitted for the same period (mandatory first step)
• GSTR-2B downloaded — your auto-drafted ITC statement from supplier filings
• RCM liability details — purchases from unregistered dealers, specified services
• Cash ledger balance — verify if you have enough credit to offset liability
• Interest calculation — if paying after due date, compute 18% p.a. interest

Step-by-Step: How to File GSTR-3B Online

Step 1 — Login and Go to Returns Dashboard

Login to gst.gov.in, navigate to Services → Returns → Returns Dashboard, select your Financial Year and return period, then click Search.

Step 2 — Click on GSTR-3B Tile → Prepare Online

Select "Prepare Online" to fill the return directly on the portal.

Step 3 — Answer the Questionnaire

The portal first asks: "Do you have any supplies, inward supplies attracting reverse charge, or any taxes to pay?" If all figures are nil, you can select Yes to nil return here and skip directly to filing — a major time-saver.

Step 4 — Review Auto-Populated Table 3 (Outward Supplies — Now Locked)

From July 2025, you'll see Table 3 is pre-filled and grayed out. Do not try to edit it. Verify the figures match your GSTR-1. If there's a discrepancy, stop — file GSTR-1A to amend GSTR-1 first, then return to GSTR-3B.

Step 5 — Fill Table 4 — Eligible ITC from GSTR-2B

Enter ITC available from GSTR-2B in four sub-sections:

• 4A(1) — Import of goods
• 4A(2) — Import of services
• 4A(3) — Inward supplies attracting reverse charge (other than 1 & 2)
• 4A(5) — All other ITC (from your suppliers' GSTR-1)

Also fill Table 4B — ITC that must be reversed (used for personal purposes, blocked credits under Section 17(5), etc.)

Step 6 — Fill Table 5 — Exempt, Nil, Non-GST Inward Supplies

If you've received any purchases that are exempt from GST, nil-rated, or non-GST goods/services, report the consolidated value here.

Step 7 — Fill Interest and Late Fees (If Applicable)

If filing after the due date, compute and enter:

• Interest: 18% p.a. on net tax liability from due date to payment date
• Late fee: As applicable per turnover slab

Step 8 — Save and Preview Draft

Click "Save GSTR-3B" — this saves but does not submit. Download the preview PDF and verify all numbers one final time.

Step 9 — Offset Tax Liability and Pay

Click "Proceed to Payment." The portal shows your total tax liability and available ITC credit. Offset ITC against liability in the correct order:

Step 10 — File with DSC or EVC, Save ARN

After payment, check the declaration, select the authorised signatory, and file using DSC or EVC. Save the ARN (Acknowledgement Reference Number) — this is your proof of filing.

How Do You File a Nil GSTR-3B?

If you had zero outward supplies, zero ITC claims, and zero tax to pay for the period:

SMS nil filing is available for both monthly and quarterly filers.

ITC Rules in GSTR-3B — What You Can and Cannot Claim

Eligible ITC (Table 4A)

You can claim ITC on:

• Purchases used exclusively for taxable business purposes
• Capital goods used in the course of business
• Input services used for business

Ineligible ITC — Must Be Reversed (Table 4B)

You cannot claim ITC on:

• Motor vehicles (with limited exceptions)
• Food, beverages, outdoor catering
• Health services and club memberships
• Personal use purchases
• Construction of immovable property

ITC Utilisation Order

Late Fee and Interest for GSTR-3B

Interest on unpaid tax: 18% per annum from the due date to the actual date of payment, computed on the net tax liability after ITC offset.

Common Errors to Avoid

• Not reconciling GSTR-2B before claiming ITC — Claiming ITC not reflected in GSTR-2B leads to notices and demands.
• Trying to edit locked Table 3 — From July 2025, this is not possible. Fix errors via GSTR-1A instead.
• Missing PMT-06 payment under QRMP — Tax must be paid monthly even though the return is quarterly. Missing the 25th deadline attracts interest.
• Filing in wrong period — GSTR-3B cannot be transferred between periods once filed.
• Ignoring IGST utilisation order — Using CGST credit against SGST (or vice versa) is not permitted.

Conclusion

GSTR-3B is where your GST compliance becomes real — it's the return that settles your tax account with the government. With the July 2025 locking of Table 3, the GSTR-1 → GSTR-3B sequence is now automated and enforced by the portal itself.

Your FY 2025–26 checklist every period:

Use our GST Calculator to verify your tax breakdowns before filing.

GST Portal — official GSTR-3B filing

GSTR-3B — Frequently Asked Questions

Related: How to File GSTR-1 · Input Tax Credit Under GST · Reverse Charge Mechanism