GST Late Fee and Interest Calculator for Delayed Returns
A late GSTR-3B costs a daily fee and 18% interest on tax paid late. The fee stops at a cap but interest keeps growing, so the cost curve changes shape after about 200 days for a regular return. This tool draws that curve for your numbers.
Your numbers
Interest applies on the net tax liability paid in cash after the due date.
The daily amount is CGST plus SGST combined. Many turnover-based concessions and caps exist, so check the current notification.
Your results
Reduced late fee caps and amnesty schemes have been notified from time to time. Confirm against the current CBIC notifications.
Cost of delay vs days late
Sweeps Days of delay from 0 to 180, holding your other inputs fixed.
Month-end GST close checklist
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How to use it
Enter the net tax you paid in cash after the due date, how many days late the return or payment was, and whether the return carried any liability. The late fee is the daily amount times the days, limited by the cap. Interest is simple interest on the late tax. Read the total cost and the chart. Use it before deciding whether to file immediately and pay later or to wait for funds, because interest and fee run in parallel.
The formulas
Late fee equals the number of days times the daily rate (Rs 50, made up of Rs 25 CGST and Rs 25 SGST, or Rs 20 for a nil return), limited to the cap. Interest equals tax paid late times 18% times days divided by 365. Interest is charged only on the tax payable in cash, not on the part covered by input tax credit. If the return is late but the tax was paid on time, interest does not arise although the fee still does.
- Fee runs from the day after the due date to the date of filing.
- Interest runs from the day after the due date to the date of payment.
- Late fee for GSTR-1 follows the same logic with its own due date.
Practical guidance
Delays most often come from a missing vendor invoice, a stuck e-invoice or an unreconciled ITC claim. File the return with the liability you can support and correct the rest in the next period instead of waiting for perfection. Keep a monthly closing calendar in your accounting package, with a task for GSTR-1 on the 11th and GSTR-3B on the 20th. Remember that unfiled returns can block e-way bill generation and your customers' ITC.
Frequently Asked Questions
Is interest on the full tax or only cash tax?
Interest applies to the net tax payable in cash, after set-off with input tax credit, and it was clarified that the cash ledger portion is the base. Check with your consultant for cases where ITC was wrongly utilised.
Can the late fee be waived?
The government has notified waivers and reduced caps from time to time, often linked to turnover or to amnesty windows. The tool uses the default caps, so compare with the current notification before paying.
Is the fee charged for GSTR-1 too?
Yes, a late fee applies to GSTR-1 with its own due date and daily amount. Use the same logic in this tool to estimate, then confirm the amount shown on the portal when you file.
Why is interest simple, not compound?
GST interest is charged as simple interest on the tax outstanding for each day. The tool therefore multiplies by days over 365. It is different from interest under the MSMED Act, which compounds monthly.
Netray can connect to your ERP or accounting database and build a close checklist that warns you when vendor invoices or e-invoices are still pending before the return due date.
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