Key takeaways
What this article covers, in order:
- Late fee and interest aren't the same thing
- How much is the late fee?
- How is interest calculated?
- Example 1: Deepak, fifteen days late
- Example 2: a nil return, forgotten for 45 days
- Example 3: two months late, with tax due
Deepak missed his GSTR-3B by fifteen days during his daughter's wedding. When he finally logged in, the portal wanted ₹750 in late fee and some interest on top. Not a disaster, but annoying. GST charges two separate things when you're late: a late fee for filing late (₹50 a day, or ₹20 for nil returns, with turnover-based caps) and interest at 18% a year on any tax you pay late in cash. Here's how each works, with real numbers.
Late fee and interest aren't the same thing
People mix these up all the time, so let's get it straight.
The late fee is a charge for filing the return late. It applies even if you owe no tax. It's per day, and it stops growing once it hits a cap.
Interest is a charge for paying tax late. It applies only when there's tax to pay, and only on the part you pay in cash. It has no cap. It keeps running until you pay.
So a nil return filed late attracts a late fee but no interest. A return with tax due filed late attracts both.
How much is the late fee?
For GSTR-1 and GSTR-3B, the late fee is ₹50 a day, split ₹25 CGST and ₹25 SGST. For nil returns, it's ₹20 a day, ₹10 under each head. The fee counts from the day after the due date to the day you file.
Then the cap kicks in. Since Jun 2021, the maximum per return depends on your previous year's aggregate turnover.
| Situation | Daily late fee | Maximum per return |
|---|---|---|
| Nil return (any turnover) | ₹20 | ₹500 |
| Turnover up to ₹1.5 crore | ₹50 | ₹2,000 |
| Turnover above ₹1.5 crore up to ₹5 crore | ₹50 | ₹5,000 |
| Turnover above ₹5 crore | ₹50 | ₹10,000 |
These caps come from CBIC notifications issued in 2021 and still apply as of Oct 2026. If you're filing for an older period or the rules have since changed, the figure the portal shows is the one you'll pay.
Two things catch people out. The late fee must be paid in cash from your electronic cash ledger; you can't use input tax credit for it. And for GSTR-1, the late fee isn't paid inside GSTR-1 itself; the portal collects it through your GSTR-3B.
How is interest calculated?
Interest under Section 50(1) is 18% a year on tax paid late in cash. It's worked out for the actual number of days late.
The formula is simple:
Interest = cash tax paid late × 18% × days late ÷ 365
Notice the words "in cash". Since the law was amended, interest is charged on the net tax you pay from the cash ledger after using your credit, not on your gross liability. That's a big relief for businesses with lots of purchases.
There's one more kind. If you wrongly claimed input tax credit and actually used it, Section 50(3) charges interest too, also at 18% a year, from the date you used it until you reverse it or pay. Older articles quote 24% for this. That was the earlier position; the rate was brought down to 18% with effect from 1 Jul 2017 by an amendment in 2022.
Example 1: Deepak, fifteen days late
Deepak runs a furniture showroom in Lucknow with turnover of about ₹1.2 crore. His Sep 2026 GSTR-3B was due on 20 Oct 2026. He filed on 4 Nov 2026, 15 days late, and paid ₹40,000 in cash after using his credit.
His late fee is 15 days × ₹50 = ₹750 (₹375 CGST and ₹375 SGST). That's under his ₹2,000 cap, so he pays the full ₹750.
His interest is ₹40,000 × 18% × 15 ÷ 365 = about ₹296.
Total extra cost: roughly ₹1,046. Irritating, but it could've been a lot worse.
Example 2: a nil return, forgotten for 45 days
Farah is a freelance photographer in Kolkata who had no work in Aug 2026. She forgot to file her nil GSTR-3B, due 20 Sep 2026, and filed it on 4 Nov 2026, 45 days late.
At ₹20 a day, 45 days comes to ₹900. But the cap for nil returns is ₹500, so she pays ₹500. No interest, because there was no tax.
If she'd also missed her nil GSTR-1 for Aug 2026, she'd face a separate late fee for that too. Each return has its own fee and its own cap.
Example 3: two months late, with tax due
Vikram runs a printing business in Chandigarh with turnover of ₹80 lakh. He's a monthly filer who missed his Jul 2026 GSTR-3B (due 20 Aug 2026) and filed it 60 days late, on 19 Oct 2026, paying ₹1,00,000 in cash.
Late fee: 60 × ₹50 = ₹3,000. His cap is ₹2,000, so he pays ₹2,000.
Interest: ₹1,00,000 × 18% × 60 ÷ 365 = about ₹2,959.
Total: around ₹4,959. And because the portal blocks GSTR-1 when the previous GSTR-3B is pending, his Aug 2026 GSTR-1 would also have been held up. The knock-on effects often cost more than the fee itself.
What about the annual return?
GSTR-9 has its own late fee, worked out per day with caps linked to your turnover in that year. The structure was revised in 2023 so that smaller businesses pay a lower daily rate and a lower cap. The exact numbers depend on your turnover band, so check the portal's figure for your case. GSTR-9 for FY 2025-26 is due on 31 Dec 2026.
Ways to keep the bill small
File the nil return even when you're busy. It takes ten minutes, or an SMS, and caps at ₹500 if you're late. Ignoring it for a year across two returns adds up.
Deposit the tax on time, even if the return is late. This one's little known. Since Jul 2024, Rule 88B says that if you put the tax into your electronic cash ledger by the due date, and it stays there until your late GSTR-3B uses it, no interest is charged on that amount. You'll still owe the late fee for filing late, but the interest part goes away. Keep the challan receipt as proof of the date, and ask your CA if your case has any twist.
Don't let one late return block the next. The portal's sequencing rules mean a pending GSTR-3B stops your next GSTR-1. One late return can quickly become three.
Watch the three-year bar. Returns more than three years past their due date can't be filed any more. That's not a late fee problem. That's a "you can never fix this" problem.
If you're looking at months of unfiled returns, notices or a cancelled registration, sit down with a CA before you start filing. The order you file in can make a difference.
How HelloBooks helps
When you file GSTR-3B from HelloBooks, any interest and late fee are shown as the GST portal's own figure before you file, so you know exactly how much cash you need. There's no estimate that turns out wrong at the payment step. Both GSTR-1 and GSTR-3B are filed directly to the GST portal from inside HelloBooks.
On HelloBooks Free (₹0, no card, no expiry), GSTR-1 and GSTR-3B filing is unlimited for one GSTIN, with GSTR-2B reconciliation, 2 users and up to 200 transactions a year. More on the GSTR-3B filing page and the full list of GST returns.
FAQs
Is there a late fee on a nil GSTR-3B?
Yes. ₹20 a day (₹10 CGST plus ₹10 SGST), capped at ₹500 per return. There's no interest, since there's no tax.
Can I pay the GST late fee using input tax credit?
No. Late fee has to be paid in cash through the electronic cash ledger.
Is interest charged on my total GST or only the cash part?
Only on the net tax paid late in cash, after setting off your input tax credit.
If I file both GSTR-1 and GSTR-3B late, do I pay two late fees?
Yes. Each return has its own daily fee and its own cap. Missing both for the same month means two separate charges.
Can the late fee be waived?
The government has announced amnesty schemes in the past for older periods, with reduced fees for a limited window. There's no automatic waiver; check the portal and CBIC notifications for anything currently open.
Ten minutes on the 18th is cheaper than any of the examples above. Set the reminder.
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