GST Interest Calculator
Paid GST after the due date? Pick the tax period, enter the date you paid and the tax you settled in cash, and see the Section 50 interest and GSTR-3B late fee you owe, down to the rupee.
Tax period and due date
QRMP 22nd: Chhattisgarh, MP, Gujarat, Maharashtra, Karnataka, Goa, Kerala, Tamil Nadu, Telangana, AP, Puducherry and the islands. Most other states and UTs use the 24th. You can change the due date if an extension was notified.
ITC wrongly availed and used optional
GSTR-3B late fee optional
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How to calculate GST interest
GST interest under Section 50 of the CGST Act is simple interest at 18% a year on the tax paid late, counted for the actual days of delay. Only the part you pay in cash attracts interest. The part set off against input tax credit does not.
The net GST you settle from the electronic cash ledger after using ITC. Take it from the "paid in cash" column of Table 6.1 in your GSTR-3B.
Example: liability ₹20 lakh, ITC used ₹7.5 lakh, cash ₹12.5 lakhThe Section 50(1) rate for tax paid late, and the notified rate for ITC wrongly availed and used. It is a yearly rate, so it is scaled by days.
Example: 18% a year is about 0.049% a dayCalendar days from the day after the GSTR-3B due date up to the date the cash is debited. Read the due date from the GST calendar and the payment date from your challan or cash ledger.
Example: due 20 Oct, paid 15 Nov = 26 days| Tax paid in cash | ₹5,00,000 |
| Due date (September return) | 20 Oct 2026 |
| Paid on | 4 Dec 2026 |
| Days of delay | 45 |
| Interest at 18% | ₹11,096 |
- Find the due date: 20th of the month after the tax period, or the 22nd or 24th after the quarter for QRMP filers
- Count the days from the day after the due date to the payment date: 21 Oct to 4 Dec is 45 days
- Multiply the cash portion by 18% and by days ÷ 365: 5,00,000 × 0.18 × 45 ÷ 365 = ₹11,096
- Pay it under the same head (CGST, SGST or IGST) as the late tax, through the cash ledger
GST interest rates and late fee rules
Two interest rates and one late fee schedule cover almost every GSTR-3B case. Late fee caps depend on your aggregate turnover in the previous financial year.
| Situation | Rate or fee | How it works |
|---|---|---|
| Tax paid after the due date (Section 50(1)) | 18% a year | On the cash portion only, from the day after the due date to the payment date |
| ITC wrongly availed and used (Section 50(3)) | 18% a year | Notified rate under rule 88B, from the date the credit was used to the date it is reversed or paid |
| GSTR-3B late fee, with tax | ₹50 a day | ₹25 CGST plus ₹25 SGST, until the return is filed |
| GSTR-3B late fee, nil return | ₹20 a day | Capped at ₹500 a return |
| Late fee cap, turnover up to ₹1.5 Cr | ₹2,000 | Per return, CGST and SGST together |
| Late fee cap, ₹1.5 Cr to ₹5 Cr | ₹5,000 | Per return, CGST and SGST together |
| Late fee cap, above ₹5 Cr | ₹10,000 | Per return, CGST and SGST together |
Based on Section 50 of the CGST Act, Notification 9/2022-CT and the late fee notifications for GSTR-3B. Check the GST portal for any notified extension before you pay.
Get a one-page summary of the due date, days delayed, interest by head and late fee for this return.
How to avoid GST interest and late fees
Interest builds up every day, so most of the saving comes from closing the books early enough to file and pay on time.
Match GSTR-2B with the purchase register a few days before the due date. Teams that run a GSTR-3B vs books reconciliation each month catch gaps before they turn into interest.
Interest only runs on the cash portion. Claiming every eligible credit on time lowers the cash you pay and the interest on it.
You can deposit tax through a challan before the return is ready. The interest clock stops when the cash ledger is debited.
If a supplier has not filed, reverse the credit before using it. Interest under Section 50(3) only starts once wrong credit is used.
QRMP filers pay monthly through PMT-06 by the 25th. Missing it brings interest even when the quarterly return is on time.
Portal slowdowns near the 20th are common. An internal deadline of the 18th leaves room for a failed payment.
Frequently asked questions
Multiply the tax paid late in cash by 18% and by the days of delay, then divide by 365. For ₹5 lakh paid 45 days late, interest is 5,00,000 × 0.18 × 45 ÷ 365 = ₹11,096.
On the net cash liability. The proviso to Section 50(1), effective from 1 July 2017, limits interest to the part of tax paid through the electronic cash ledger. The part set off against ITC is not charged interest.
18% a year, but only when the wrong credit was both availed and used. Section 50(3) allows up to 24%, and the government has notified 18% through Notification 9/2022-CT. Credit that was availed but never used does not attract interest.
It depends on turnover. The fee is ₹50 a day (₹20 for nil returns), capped at ₹2,000 up to ₹1.5 crore turnover, ₹5,000 from ₹1.5 to 5 crore and ₹10,000 above ₹5 crore. Nil returns are capped at ₹500.
From the day after the due date to the day the tax is actually paid. For a September monthly return due on 20 October, interest starts on 21 October.
No. Interest and late fee have to be paid in cash from the electronic cash ledger. They are reported in Table 5.1 of the next GSTR-3B or paid through DRC-03.
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