GSTR-3B: What It Is and How to File It Without Mistakes

Due dates

• Monthly filers: by the 20th of the next month.
• QRMP (quarterly) filers: by the 22nd or 24th of the month after the quarter, depending on your state. In the first two months of the quarter, tax is paid through challan PMT-06 by the 25th.
• Interest at 18% per year applies on tax paid late (on the part paid in cash), plus a daily late fee for late filing.

The important tables

Scroll sideways to see all columns.

Step-by-step monthly routine

1. Finish and file GSTR-1 for the period, so the sales figures are final.
2. Open your GSTR-2B (available around the 14th of the next month). It lists the ITC your suppliers have reported for you.
3. Match GSTR-2B with your purchase bills. Claim ITC only for bills that appear in 2B and meet the other conditions; follow up with suppliers whose bills are missing. See the input tax credit guide.
4. Open GSTR-3B on the portal. Check the auto-filled values in table 3.1 against your sales register and table 4 against your matched purchases.
5. Save, then go to Payment of tax. The portal sets off ITC against output tax in the order the law requires (IGST credit is used first).
6. If cash is needed, create a challan (PMT-06) and pay by net banking, UPI or card, or over the counter. Then offset liability and file with DSC or EVC.

Using BizBahi for GSTR-3B

The GSTR-1 / 3B export in BizBahi (More → GSTR-1 / 3B export, paid plans and the 7-day trial) shows a month-wise GSTR-3B summary from your saved data: taxable outward supplies with IGST, CGST and SGST, nil-rated sales, inter-state sales to unregistered buyers by state, ITC from the purchase bills you entered, and the net tax payable.

Before relying on that ITC figure, use More → GSTR-2B matching: import the GSTR-2B JSON or Excel downloaded from the portal, and BizBahi shows which purchase bills match, which have different amounts and which suppliers have not reported your bill. It only reads; it does not change your books. You still file and pay on the GST portal yourself.

Mistakes that lead to notices

• Output tax in GSTR-3B lower than the tax in GSTR-1 for the same period.
• Claiming ITC that is not in GSTR-2B, or claiming blocked credits such as food and beverages for staff.
• Forgetting reverse charge tax in 3.1(d). Reverse charge tax must be paid in cash; it cannot be paid from ITC.
• Not reversing ITC when you have not paid your supplier within 180 days of the invoice date.
• Filing nil GSTR-3B when there were actually sales, just to save time. Late fee is cheaper than the penalty and interest later.

Can I revise GSTR-3B after filing?

No. A filed GSTR-3B cannot be revised. Correct the error in the next period’s return and pay any interest due.

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

GSTR-1 reports sales invoice by invoice. GSTR-3B is a summary of sales tax, input tax credit and the tax you pay. Both must agree with each other.

Is GSTR-3B needed for months with no business?

Yes. File a nil GSTR-3B, which can also be filed by SMS if you qualify.

Where does the ITC in GSTR-3B come from?

From your eligible purchase bills, checked against GSTR-2B, which shows what your suppliers reported in their GSTR-1.