Can I use input tax credit to pay the GST late fee or interest?

No. Input tax credit (ITC) can only pay the tax itself. The late fee and the interest must be paid from your electronic cash ledger, which is the account you top up with a bank payment. Example: you owe ₹500 as late fee and interest but have only ₹300 in the cash ledger. Add ₹200 first, or you can't file.

Does the late fee stop growing at some point? Does the interest?

The late fee stops at a maximum, called the cap. For a business with turnover up to ₹1.5 crore, the cap is ₹2,000. The interest has no cap. Example: after 40 days at ₹50 a day, the late fee has reached ₹2,000 and stays there, but interest keeps growing every day until you pay.

Is interest charged on all my tax or only part of it?

Only on the part you pay in cash, after ITC is used. Example: your tax is ₹5,00,000 and your ITC is ₹4,20,000. You pay ₹80,000 in cash, so interest is charged on ₹80,000 only. If ITC covers all of the tax, there is no interest, but the late fee still applies.

From which date do I count the days of delay?

Start from the day after the due date and stop on the day you file and pay. Example: the due date is 20 October. Filing on 20 October is on time. Filing on 21 October is 1 day late. Filing on 25 October is 5 days late.

Where do I see the interest and late fee on the GST portal?

In Table 5.1 of GSTR-3B, which is called interest and late fee payable. Check the amounts there before you pay and file.

GST Late Fee and Interest: How It's Worked Out (3 Examples)

If you file your GST return late, you can pay two separate extra charges. The first is a late fee, which is a fixed amount for each day you are late. The second is interest, which is 18% a year on any tax you paid late. This post explains both in simple words. Every rupee figure comes with a worked example, so you can follow the maths and then try your own numbers.

For the October 2026 due dates, see GST return due dates in October 2026.

First, a few words you will see in this post

GSTR-3B: the monthly return where you pay your GST. Example: for September sales, you file it by 20 October.
GSTR-1: the monthly return that lists your sales invoices. You don't pay tax in it. Example: for September, you file it by 11 October.
GSTR-9: the yearly return that sums up the whole financial year.
Input tax credit (ITC): the GST you already paid on your purchases, which you can subtract from the GST you collected on sales. Example: you collected ₹10,000 GST on sales and paid ₹6,000 GST on purchases. You can use the ₹6,000 ITC, so you pay ₹4,000.
Cash ledger: your GST account on the portal that you fill with a bank payment. The ₹4,000 in the example above is paid from it.
Nil return: a return with no sales and no tax to pay. You still have to file it.
Aggregate turnover: your total sales for the whole previous financial year. Example: in FY 2026-27, you look at your sales for FY 2025-26.
Cap: the maximum a charge can reach. After that, it stops growing.

The two charges, side by side

	Late fee	Interest
What it is for	Filing the return after the due date	Paying the tax after the due date
Which returns	GSTR-3B, GSTR-1 and GSTR-9	Only where tax is paid, mainly GSTR-3B
How much	₹50 a day (₹20 a day for a nil return)	18% a year, worked out per day
Is there a maximum?	Yes, it depends on your turnover	No
Paid from	Cash ledger only	Cash ledger only

The late fee is split equally between CGST and SGST. Example: ₹50 a day means ₹25 CGST and ₹25 SGST for each day.

How big can the late fee get?

The maximum depends on your turnover in the previous financial year:

Your situation	Fee per day	Maximum for one return
Nil return	₹20	₹500
Turnover up to ₹1.5 crore	₹50	₹2,000
Turnover ₹1.5 crore to ₹5 crore	₹50	₹5,000
Turnover above ₹5 crore	₹50	₹10,000

Example: a shop with ₹80 lakh turnover files 3 days late. The fee is 3 × ₹50 = ₹150. It is far below the ₹2,000 maximum, so ₹150 is what it pays.

How is the interest worked out?

Use this formula:

Interest = cash tax × 18% × days late ÷ 365

Example: cash tax of ₹10,000, filed 10 days late. ₹10,000 × 18% × 10 ÷ 365 = ₹49.32, so about ₹49.

Example 1: ₹2,00,000 of cash tax, filed 5 days late

A trader had ₹1 crore turnover last year. After using ITC, they owe ₹2,00,000 in cash. The September GSTR-3B is due on 20 October. They file and pay on 25 October.

Days late: 21, 22, 23, 24 and 25 October is 5 days.
Late fee: ₹50 × 5 = ₹250. That is ₹125 CGST and ₹125 SGST. The ₹2,000 maximum is far away.
Interest: ₹2,00,000 × 18% × 5 ÷ 365 = ₹493.
Extra cost: ₹250 + ₹493 = ₹743, on top of the ₹2,00,000 tax.

Notice that interest (₹493) is nearly double the late fee (₹250). When the tax amount is large, even a short delay costs more in interest than in late fee.

Open this example in the GST Late Fee Calculator and change the numbers to your own.

Example 2: when the late fee reaches its maximum

Same trader, same ₹2,00,000 of cash tax. This time the return is filed on 19 December, which is 60 days late.

Late fee: 60 × ₹50 would be ₹3,000. But the maximum for turnover up to ₹1.5 crore is ₹2,000. The fee reached ₹2,000 on day 40 (40 × ₹50 = ₹2,000) and then stopped.
Interest: ₹2,00,000 × 18% × 60 ÷ 365 = ₹5,918.
Extra cost: ₹2,000 + ₹5,918 = ₹7,918.

After day 40, the late fee does not grow any more, but interest keeps growing every single day. So if you have missed a return, file it as soon as you can. Waiting does not save money.

Open this example in the calculator

Example 3: a return where ITC covers most of the tax

Interest is charged only on the part you pay in cash, not on the full tax. Here is how that works.

A business has ₹5,00,000 of GST to pay for the month. It has ₹4,20,000 of ITC, which it subtracts. That leaves ₹80,000 to pay in cash (₹5,00,000 − ₹4,20,000). It files 12 days late, on 1 November instead of 20 October. Its turnover last year was ₹1 crore.

Late fee: ₹50 × 12 = ₹600.
Interest: ₹80,000 × 18% × 12 ÷ 365 = ₹473. A common mistake is to use the full ₹5,00,000. That would give ₹2,959, which is wrong.
Extra cost: ₹600 + ₹473 = ₹1,073.

Also notice that the late fee does not depend on the tax amount. A return with ₹5,00,000 of tax and a return with ₹5,000 of tax pay the same late fee for the same number of days late.

Open this example in the calculator

GSTR-1 and GSTR-3B: what is different?

The late fee is the same for both. The difference is that GSTR-1 has no tax payment.

Late GSTR-1: you pay the late fee, but no interest, because there is no tax in this return. Example: GSTR-1 filed 4 days late with turnover up to ₹1.5 crore costs 4 × ₹50 = ₹200. That is all.
Late GSTR-3B: you pay the late fee, and interest on any cash tax paid late. That is Example 1 above.

A late GSTR-1 has another cost that does not show up as a charge. Your buyers cannot see your invoices in their GSTR-2B until you file. Example: you sell goods to a customer in September but file GSTR-1 late. Your customer may not be able to claim ITC for that purchase in September. This can upset a good customer.

GSTR-9, the yearly return, has its own late fee

The yearly return has a different table. The fee per day depends on the turnover for the financial year the return covers, and the maximum is a small percentage of that turnover. These figures are combined CGST and SGST.

Turnover	Fee per day	Maximum
Up to ₹5 crore	₹50	0.04% of turnover
₹5 crore to ₹20 crore	₹100	0.04% of turnover
Above ₹20 crore	₹200	0.5% of turnover

GSTR-9 is due by 31 December after the financial year ends.

Example: a business with ₹3 crore turnover files GSTR-9 10 days late. The fee is 10 × ₹50 = ₹500. The maximum is 0.04% of ₹3 crore = ₹12,000, so ₹500 is what it pays.

The GST Late Fee Calculator covers GSTR-9 as well as GSTR-3B and GSTR-1.

Common mistakes, with examples

Paying only the late fee. The portal shows a late fee when you file, so it is easy to think that is all. Example: the late fee is ₹250 but interest is ₹493. If you plan for ₹250, you are ₹493 short. Check Table 5.1 of GSTR-3B for both amounts.
Thinking the maximum limits everything. The maximum applies to the late fee only. Interest has no maximum (Example 2).
Working out interest on the full tax. It is on the cash part, after ITC (Example 3).
Using this year's turnover. The late fee slab uses the previous financial year. Example: in FY 2026-27, use your FY 2025-26 turnover.
Waiting for a waiver. CBIC has reduced or waived late fees before, but only by a notification for specific returns and periods. We have not seen one for the September 2026 GSTR-3B or GSTR-1. If you are counting on one, read the notification and its conditions first.
Hoping a holiday will move the date. A GST due date does not move for a Sunday or a public holiday. Example: if the due date falls on a Sunday, the late fee starts on Monday. Only a CBIC notification can extend a date.

How to check your own figure in 4 steps

Find your due date in the GST Return Due Date Calendar.
Note the day you filed, or the day you plan to file.
In the GST Late Fee Calculator, choose your turnover slab, or nil return.
Enter your cash tax after ITC. The calculator shows the late fee, the interest and the total.

Always check the final amount in Table 5.1 on the GST portal when you file. That is the amount the portal will ask you to pay.

Sources

The rates and maximums in this post are the ones in force on 5 October 2026. Check the GST portal before you file.