GST interest is 18% a year on the tax you pay late in cash, for each day after the due date. The late fee for GSTR-3B or GSTR-1 is ₹50 a day (₹20 for a nil return), up to a limit based on your turnover. Enter your dates and amounts below to see both, using the same formula as the GST portal.
This is a guide, not the GST portal's figure. The portal works out interest for each tax head (IGST, CGST, SGST, cess), so its total can differ slightly. It does not include penalties.
This calculator works out two separate charges. The late fee is for filing a return late. The interest is for paying tax late. If your GSTR-3B is late, you usually pay both.
For the due dates themselves, see GST return due dates.
Late fee limits (one return, for returns from June 2021):
| Your case | Per day | Maximum |
|---|---|---|
| Nil return | ₹20 | ₹500 |
| Turnover last year up to ₹1.5 crore | ₹50 | ₹2,000 |
| Above ₹1.5 crore, up to ₹5 crore | ₹50 | ₹5,000 |
| Above ₹5 crore | ₹50 | ₹10,000 |
Each figure is the total of the CGST part and the SGST or UTGST part, which are equal. The full rules and examples are in our guide to the GST late fee for GSTR-1 and GSTR-3B.
Our reading: GSTN's interest formula divides by “the number of days in the year”. We use 365, as published summaries of GSTN's 2026 formula do.
From the January 2026 tax period, the GST portal works out the interest on a late GSTR-3B by itself. It shows the amount in Table 5.1 of your next GSTR-3B.
The rule behind this is rule 88B of the CGST Rules. The 2026 change is in how the portal applies it.
Interest on late GST comes from section 50 of the CGST Act. The GST portal works it out for each tax head (IGST, CGST, SGST or UTGST, and cess).
| Part of section 50 | What it says, in short | Rate |
|---|---|---|
| Section 50(1) | Tax paid after the due date carries interest for the days it stays unpaid. | 18% a year |
| Proviso to 50(1) | When you file a return late, interest is only on the tax you pay in cash. Tax paid with input tax credit carries no interest. This does not apply if the return is filed after the officer has started proceedings for that period (sections 73, 74 or 74A). | |
| Section 50(2) | Interest runs from the day after the tax was due. | |
| Section 50(3) | Input tax credit that was wrongly taken and used carries interest. | 18% a year |
18% or 24%? It is 18% for both. The law lets the government set up to 24% for wrongly used input tax credit, and 24% was the rate first notified in 2017. The Finance Act, 2022 cut it to 18% with effect back to 1 July 2017. So interest on a late payment and interest on wrongly used credit are both 18% a year today.
Interest, like the late fee, is paid in cash. Input tax credit can pay only output tax. See cash or input tax credit.
| Late fee | Interest | Penalty | |
|---|---|---|---|
| Why you pay it | Filing a return late | Paying tax late | A breach found by an officer |
| How much | ₹50 a day (₹20 nil), with a limit | 18% a year on tax paid late in cash | Set in a notice or order |
| Who works it out | The GST portal, in a later GSTR-3B | The GST portal (from January 2026), in your next GSTR-3B | The tax officer |
| In this calculator | Yes | Yes | No |
Our reading: if you searched for a “GST penalty calculator”, the late fee is most likely what you need. A real penalty under the GST law comes only with a notice or order from an officer, so no calculator can tell you that amount in advance.
Can the late fee be waived? Only the government can waive it, by a notification. At its 57th meeting on 8 October 2026, the GST Council recommended waiving the late fee on a GSTR-3B filed by the end of the month in which it was due, for turnover up to ₹5 crore. As of 18 October 2026, this has not been notified, so this calculator still adds the normal late fee. Interest would be payable even after such a waiver. More in can the GST late fee be waived.
Need to file the late returns first? See what to do if you missed a due date.
Interest = tax paid late in cash × 18% × days late ÷ 365. The days run from the day after the due date to the day you pay. For a late GSTR-3B, the tax that was already in your cash ledger from the due date is left out.
18%. The law allows up to 24% for input tax credit wrongly taken and used, but the Finance Act, 2022 set that rate at 18% from 1 July 2017. Interest on late payment of tax is also 18% a year.
18% a year, for each day the tax stays unpaid after the due date. It is charged only on the part paid in cash when you file a late return.
Days late × ₹50 for each return (₹20 for a nil return), up to a limit. The limit is ₹500 for a nil return, and ₹2,000, ₹5,000 or ₹10,000 based on your turnover in the last financial year.
₹500 for a nil return. Otherwise ₹2,000 if your turnover last year was up to ₹1.5 crore, ₹5,000 up to ₹5 crore, and ₹10,000 above ₹5 crore. The same limits apply to GSTR-1.
₹20 a day (₹10 CGST and ₹10 SGST), and never more than ₹500 for one return. A nil GSTR-3B means no tax to pay; a nil GSTR-1 means no sales.
From the January 2026 tax period, the GST portal works out the interest on a late GSTR-3B and fills it into your next GSTR-3B. It leaves out cash that was already in your cash ledger from the due date. You can raise the figure but not lower it.
No. The portal's figure is the least you must pay. If you think it is wrong, check the dates and your cash ledger balance. You can enter a higher amount if your own working shows more.
Only on the cash part, when you file a late return. Tax paid with input tax credit carries no interest. This changes if the return is filed after an officer has started proceedings for that period.
No. Input tax credit can pay only output tax. Late fee and interest are paid in cash, from the Electronic Cash Ledger.
Yes. Enter the due date of your quarterly GSTR-3B (22nd or 24th, by State) or quarterly GSTR-1 (13th).
Only by a government notification. The GST Council recommended a waiver for some late GSTR-3B returns on 8 October 2026, but as of 18 October 2026 it had not been notified.
No. A late fee is a fixed charge for filing late, worked out by the portal. A penalty is set by a tax officer in a notice or order. This calculator does not work out penalties.
No. A return cannot be filed once three years have passed from its due date, and the GST portal blocks it.
Har return par ₹50 roz (nil return par ₹20 roz). Maximum nil return par ₹500, aur baaki returns par pichhle saal ke turnover ke hisaab se ₹2,000, ₹5,000 ya ₹10,000.
Cash mein bhara gaya late tax × 18% × late din ÷ 365. Jo paisa due date se cash ledger mein pada tha, us par interest nahi lagta.