GSTR-3B Filing: A Step-by-Step Guide

To understand how to file GSTR-3B, think of it as your monthly GST summary-and-payment return. You log in to gst.gov.in, report your total outward supplies and output tax, claim your eligible input tax credit (ITC), let the two net off, pay any balance, and file. Unlike GSTR-1, GSTR-3B is summary-level, so you report totals, not individual invoices.

What is GSTR-3B?

GSTR-3B is a self-declared summary return where a GST-registered business reports its total sales, total purchases eligible for credit, the tax payable, and the tax paid for a tax period. It is the return through which you actually pay your GST.

It is not invoice-level. You do not list each invoice; you report consolidated figures. That makes it different from GSTR-1, which is detailed and invoice-wise. For how the two differ, read GSTR-1 vs GSTR-3B, and for the wider system see our GSTR-1 filing guide.

Every normal taxpayer files GSTR-3B, even with zero activity (a Nil return). Composition dealers are excluded; they have their own returns.

Before you start (data you need)

GSTR-3B is a summary, so you need totals that match your books and your GSTR-1.

• Total outward supplies for the period, split into taxable, zero-rated, exempt, and nil-rated.
• Output tax payable, split into IGST, CGST, SGST/UTGST, and cess.
• Eligible ITC from your purchases, cross-checked against your auto-generated GSTR-2B.
• Inward supplies under reverse charge (RCM), if any.
• Ineligible or reversed ITC details.
• Cash and credit ledger balances already on the portal.

Always reconcile your ITC with GSTR-2B before you claim. Claiming more credit than GSTR-2B supports is the fastest way to attract a notice.

Step-by-step: how to file GSTR-3B

1. Log in to gst.gov.in and open the Returns Dashboard.
2. Select the financial year and tax period, then choose GSTR-3B and click Prepare Online.
3. Table 3.1 - Outward supplies: Enter total taxable supplies and the output tax (IGST, CGST, SGST, cess). Add zero-rated, exempt, and nil-rated supplies.
4. Table 3.2: Report inter-state supplies made to unregistered persons, composition dealers, and UIN holders.
5. Table 4 - ITC: Enter eligible ITC, then any ITC to be reversed, to arrive at net ITC. Reconcile against GSTR-2B.
6. Table 5: Report values of exempt, nil-rated, and non-GST inward supplies.
7. Click Save and then Proceed to Payment. The portal shows tax payable after setting off ITC.
8. Offset liability: Use the credit ledger (ITC) first, then pay any shortfall from the cash ledger by creating a challan.
9. Tick the declaration and click File GSTR-3B using DSC or EVC.
10. Download the filed return and the acknowledgement for your records.

How output tax and input tax credit net off

This is the heart of GSTR-3B. You owe tax on what you sell (output tax), and you have credit for tax already paid on what you bought (input tax credit). You pay only the difference in cash.

A simple example

Say Verma Traders in Jaipur has, for May:

• Output tax on sales: ₹50,000.
• Eligible ITC on purchases: ₹35,000.
• Net tax payable in cash: ₹50,000 − ₹35,000 = ₹15,000.

You set off the ₹35,000 from your electronic credit ledger and pay only ₹15,000 from the cash ledger. The portal applies set-off rules in a fixed order (IGST credit is used first, and so on), so follow the utilisation the system suggests.

Set-off rules to remember

• IGST credit is used to pay IGST first, then CGST or SGST in any order.
• CGST credit cannot be used to pay SGST, and vice versa.
• No credit, no problem in cash: if ITC is short, the balance is paid in cash.

For quick tax-and-credit math while preparing, our GST calculator helps.

GSTR-3B due dates and late fees

As of 2026, monthly filers generally file GSTR-3B by the 20th of the following month. QRMP (quarterly) filers file by the 22nd or 24th after the quarter, depending on their state group. These dates can change and are sometimes extended, so confirm the exact date on gst.gov.in or with your CA before each filing.

Late fees and interest (hedge)

If you miss the deadline, you typically face a per-day late fee (with a separate, lower rate for Nil returns) plus interest on the unpaid tax, charged per annum on the net cash tax liability. The exact late-fee and interest amounts are set by notification and have changed over time. Treat any figure you read as indicative and verify the current rates on the official portal. Our GSTR-1 due dates and late fees page covers the related sales-return deadlines.

One practical point: late or non-filing of GSTR-3B can block your GSTR-1 filing and your buyers' credit chain, so it compounds quickly.

Common errors to avoid

• ITC mismatch: Claiming more credit than your GSTR-2B supports. Reconcile first.
• GSTR-1 vs 3B gap: Outward tax in GSTR-3B not matching GSTR-1. Keep them aligned.
• Wrong head: Reporting IGST as CGST+SGST, or vice versa. Check inter-state vs intra-state.
• Forgetting reverse charge: RCM liability must be declared and paid in cash, not from ITC.
• Filing without paying: You cannot file GSTR-3B until the liability is fully offset.
• Skipping Nil returns: A zero-activity month still needs a filed return.

Almost every GSTR-3B error traces back to mismatched sales and purchase data. Invodo keeps your invoices GST-correct, reconciles outward tax with your GSTR-1, and gives you clean summary totals so your GSTR-3B ties out the first time. Create your free Invodo account and stop dreading the 20th.