GSTR-3B: Due Date, Late Fee, Tables and How to File (2026)

It is the 19th of the month. The shop is busy, the accountant has sent a WhatsApp message that says only "3B?", and somewhere in a drawer are last month's purchase bills. Tomorrow is the 20th, and the 20th is the day GST actually has to be paid. That return is GSTR-3B, and for most small businesses it is the one deadline that costs money every time it is missed.

This guide explains GSTR-3B in plain language: who files it, the due dates for monthly and quarterly filers (including which states file on the 22nd and which on the 24th), the late fee as it actually applies, how interest is worked out, what each table asks for, and the steps on the GST portal. It ends with the mistakes that cause notices and a short routine that keeps the 20th from being a crisis.

What is GSTR-3B?

GST has two regular returns for a normal taxpayer, and they do different jobs.

GSTR-1 lists what you sold, invoice by invoice for business buyers. It reports, but it does not pay anything. GSTR-3B is where the money moves: you state the totals, set off the input tax credit you are entitled to, and pay the balance in cash.

That makes GSTR-3B the return the tax department watches most closely. It is the one that decides whether the tax collected from your customers actually reached the government.

Takeaway: GSTR-1 tells the government what you sold. GSTR-3B pays for it.

Who has to file GSTR-3B

Every person registered as a normal taxpayer files GSTR-3B for every period, whether or not there were sales. A month with no sales, no purchases and no tax still needs a nil return.

These registrations do not file GSTR-3B:

• Composition dealers, who pay through CMP-08 every quarter and file GSTR-4 once a year. Our guide to the GST composition scheme explains how that works.
• Input service distributors, non-resident taxable persons, TDS deductors, TCS collectors and suppliers of online services from outside India, each of whom has a separate return.

Takeaway: if you are a regular GST taxpayer, GSTR-3B is due every period, even an empty one.

GSTR-3B due dates in 2026

You file either monthly or quarterly. Quarterly filing is available under the QRMP scheme (Quarterly Return Monthly Payment) to businesses with aggregate turnover up to ₹5 crore in the previous financial year.

Which states file on the 22nd and which on the 24th?

The quarterly date depends on where your business is registered.

So a quarterly filer in Tamil Nadu files the July to September return by 22 October, while one in Uttar Pradesh has until 24 October.

Dates are sometimes extended by notification. The return for March 2026, for example, was extended from 20 April to 21 April 2026. The Returns Dashboard always shows the current date for your period, so check it there rather than relying on a calendar.

Paying monthly when you file quarterly

Filing quarterly does not mean paying quarterly. For the first two months of each quarter, a QRMP taxpayer pays tax by the 25th of the next month using challan PMT-06, by one of two methods:

• Fixed sum: pay 35% of the tax you paid in cash for the last quarter. The portal pre-fills the amount.
• Self-assessment: work out the actual tax for the month, after credit, and pay that.

The third month's tax is paid with the quarterly GSTR-3B itself.

Takeaway: monthly filers pay by the 20th; quarterly filers file by the 22nd or 24th but still pay something by the 25th of each of the first two months.

The GSTR-3B late fee, as it actually applies

Search results disagree about the GSTR-3B late fee. Some say ₹200 a day, others give a single cap of ₹5,000. Both numbers are real; they just describe different layers of the law.

The CGST Act sets the late fee at ₹100 a day under CGST, and the state Acts match it, which is ₹200 a day in total. Government notifications then reduced the fee and capped it by turnover. The reduced figures are what you actually pay:

Turnover here is the aggregate turnover of the previous financial year.

The late fee is charged per return and is added automatically to your next GSTR-3B in Table 5.1. It cannot be paid from input tax credit; it is always paid in cash.

A shop with ₹80 lakh turnover that files a monthly return 12 days late pays 12 × ₹50 = ₹600 in late fee. If it files 60 days late, the fee would be ₹3,000 at the daily rate, but the cap for its turnover holds it at ₹2,000.

Takeaway: ₹50 a day is the working rate; the ₹200 figure is the law before the reduction, and the cap depends on your turnover.

Interest on late payment

The late fee is for filing late. Interest is for paying late, and it is separate. Under Section 50, tax paid after the due date carries interest at 18% a year.

Interest is charged on the net cash liability: the tax you actually pay in cash after setting off input tax credit, not on your total output tax. It runs from the day after the due date to the day you pay.

A worked example

A shop's cash payable for September is ₹40,000, due on 20 October. It pays on 30 October, 10 days late.

Add the late fee for 10 days, 10 × ₹50 = ₹500, and the cost of being 10 days late is about ₹697, all of it paid in cash.

Takeaway: interest is small for a few days, but it grows with the amount and never stops until you pay.

The GSTR-3B tables, one by one

GSTR-3B is short. Most small shops touch only three or four of its tables.

For a typical shop the work is in Table 3.1 (sales), Table 4 (credit) and Table 6.1 (payment). The rest are often blank.

Takeaway: check Tables 3.1 and 4 against your own books before you pay anything in Table 6.1.

GSTR-3B and GSTR-1: how they fit together

The two returns are linked, and the portal increasingly treats them as one system.

• Table 3 is drafted from GSTR-1. The sales you report in GSTR-1, or in the Invoice Furnishing Facility for quarterly filers, flow into the auto-drafted liability in GSTR-3B.
• Table 4 is drafted from GSTR-2B. Your input tax credit comes from what your suppliers reported in their GSTR-1. Our guide to input tax credit explains why your supplier's filing decides your claim.
• The order matters. File GSTR-1 first, then GSTR-3B. Under Rule 59(6), the portal can block a GSTR-1 for a period if the GSTR-3B for the previous period has not been filed, so falling behind on one return holds up the other.

Two changes from 2025 tightened this link further, and both are worth knowing:

• From the July 2025 tax period, the auto-populated liability in Table 3 of GSTR-3B is locked and cannot be edited there. If GSTR-1 was wrong, it is corrected through GSTR-1A before GSTR-3B is filed.
• A return cannot be filed after three years from its due date, a rule the portal began enforcing in 2025. A long-pending return can become impossible to file at all.

So the quality of your GSTR-3B now depends heavily on getting GSTR-1 right first. Our guide on how to file GSTR-1 covers that side.

Takeaway: fix sales errors in GSTR-1 or GSTR-1A, not in GSTR-3B.

A worked GSTR-3B for a small shop

Take a shop in one state with this month:

• Sales to customers within the state: ₹2,00,000 taxable at 18%
• Purchases from registered suppliers, all showing in GSTR-2B: input tax of ₹12,000 CGST and ₹12,000 SGST

The shop reports ₹2,00,000 and ₹36,000 of tax in Table 3.1, claims ₹24,000 of credit in Table 4, and pays ₹12,000 in cash. CGST credit pays CGST and SGST credit pays SGST; neither can pay the other. Our guide to the difference between CGST, SGST and IGST explains why, and the guide on how to calculate GST works through the 18% arithmetic.

Takeaway: the cash you pay is output tax minus eligible credit, head by head.

How to file GSTR-3B on the GST portal, step by step

1. Log in at gst.gov.in with your username and password.
2. Go to Services → Returns → Returns Dashboard, choose the financial year and the period, and click Search.
3. Under GSTR-3B, click Prepare Online.
4. Answer the questionnaire. It asks whether you have reverse charge supplies, e-commerce supplies, exempt inward supplies and so on, and shows only the tables you need.
5. Check the auto-filled tables. Compare Table 3.1 with your sales register and Table 4 with GSTR-2B and your purchase bills. Use the system-generated PDF summary for a side-by-side view.
6. Enter or confirm any figures that are not auto-filled, such as reverse charge liability or ineligible credit, and Save.
7. Click Proceed to Payment. The portal shows your liability head by head and offsets it against your credit ledger in the required order.
8. Pay any balance in cash by creating a challan if your cash ledger is short, then offset it.
9. Tick the declaration, choose the authorised signatory and file with EVC (an OTP to the registered mobile) or DSC. DSC is mandatory for companies and LLPs.

Once filed, GSTR-3B cannot be revised. Corrections go into a later period's return, so the time to be careful is before step 9.

Filing a nil GSTR-3B

A nil return applies when, for the period, you had no outward supplies, no input tax credit to claim and no tax liability. On the portal, answer the first question as "Yes" for a nil return and file. You can also file a nil GSTR-3B by SMS from your registered mobile number. A missed nil return still attracts the ₹20-a-day late fee, up to ₹500.

Takeaway: check before you pay; a filed GSTR-3B is final.

Common GSTR-3B mistakes

• Filing without matching GSTR-1. If the sales in GSTR-3B do not agree with GSTR-1, the gap shows up in system checks and can trigger a notice.
• Claiming credit that is not in GSTR-2B. Credit is allowed only to the extent it appears in GSTR-2B. Claiming more is the most common reason for an ITC demand.
• Forgetting reverse charge. Tax on services such as goods transport by a GTA, legal services from an advocate, or other notified supplies is paid by you as the buyer, in cash, through Table 3.1(d).
• Paying under the wrong head. Money paid as CGST cannot simply be used for SGST. A payment under the wrong head has to be corrected through the portal's transfer or refund process.
• Filing late, again and again. Continued non-filing of returns is a ground on which a GST registration can be cancelled by the department, and it also blocks e-way bills and your buyers' credit.

Takeaway: most GSTR-3B trouble starts with a figure nobody compared against the books.

A routine that keeps the 20th calm

• By the 5th: collect all purchase bills for the month and check that your suppliers' invoices are showing in the portal.
• By the 10th: close your sales for the month and file GSTR-1 by the 11th (monthly filers).
• By the 15th: open GSTR-2B, compare it with your purchase bills, and chase any supplier whose invoices are missing.
• By the 18th: work out the cash payable head by head and make sure the money is in the cash ledger.
• By the 20th: file GSTR-3B and save the filed PDF.

Quarterly filers can follow the same rhythm against the 13th for GSTR-1 and the 22nd or 24th for GSTR-3B, with PMT-06 payments by the 25th in the first two months.

Where BillZap fits in

BillZap, our free GST billing app for Android, handles the sales side of GSTR-3B. Its GST reports give month-wise taxable value with CGST, SGST and IGST totals as CSV or PDF, and a GSTR-1 ready JSON. Those are the figures that feed Table 3.1, so the sales your accountant enters come straight from the bills you made at the counter.

It is worth being clear about what it does not do. BillZap does not track purchases or input tax credit, so Table 4 still comes from GSTR-2B and your purchase bills, and it does not file returns on the GST portal. It works fully offline and needs no sign-up.

FAQ: GSTR-3B

The bottom line

GSTR-3B is where GST becomes real money. Get the order right, GSTR-1 first and GSTR-3B after, match your sales and credit against your own records before you pay, and file by the 20th (or the 22nd or 24th if you are quarterly). Do that and the return takes minutes; skip it and late fees, interest and notices follow.

The part you control most is the sales record. If you want a free app that makes every bill with the right GST and hands your accountant month-wise totals ready for Table 3.1, BillZap is on Google Play. It works offline with no sign-up.

This guide explains GSTR-3B in plain language and is not tax advice. Due dates, late fees and portal rules change by notification; confirm the current position with your chartered accountant or the GST portal before you file.