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Scan for outdated or missing drivers - takes under a minuteDriver Scan →Clear out junk files and repair common Windows errorsFree Scan →Yes, a late GSTR-3B can create two separate liabilities. A late fee is linked to furnishing the return after its due date. Interest is linked to tax that remained unpaid after its payment deadline. You may owe one, the other, or both. Calculate them independently using the due date for that return period, the date tax was discharged, the notified interest rate, and the late-fee notification applicable to your taxpayer category.
The GST Portal now also applies a specific interest calculation enhancement for tax periods from January 2026: its Table 5.1 calculation considers the minimum balance available in the Electronic Cash Ledger (ECL) between the due date and the date of tax debit. The portal amount is a minimum, not permission to ignore a higher amount that your own legal calculation establishes.
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Late fee and interest are triggered by different events
Section 47(1) of the Central Goods and Services Tax (CGST) Act deals with failure to furnish specified details or returns, including returns under section 39, by the prescribed date. That is the legal basis for a late-filing fee. Section 50 deals with interest when tax is not paid within the prescribed period. The two provisions address different compliance failures.
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| Point of comparison | Late fee | Interest |
|---|---|---|
| Trigger | GSTR-3B furnished after its applicable due date | Tax remains unpaid after the date it was due |
| Calculation base | Eligible days of filing delay multiplied by the daily amount in the applicable notification | Unpaid tax, adjusted where legally applicable, multiplied by days and the notified annual rate |
| When counting generally starts | The day after the return due date | The day after the tax payment due date under section 50(2) |
| What determines the amount | Taxpayer category, return period, liability status, statutory notifications, caps and waivers | Tax period, amount unpaid, payment or debit date, applicable notified rate and any permitted ledger adjustment |
| Portal presentation | Shown as a separate liability when the return is filed late | System-computed in Table 5.1 of the subsequent period’s GSTR-3B, with a breakup in the system-generated PDF |
| Can both apply? | Yes. A return may be filed late while tax was also unpaid, creating separate late-fee and interest obligations. | |
Paying interest does not automatically clear a late fee, and paying a late fee does not settle interest. Keep separate workings for each.
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How to identify the correct due date
Do not begin with a universal calendar date. The due date can vary with filing frequency, location or taxpayer category, and government extensions. Select the relevant tax period on the GST Portal return dashboard and record the due date displayed there. If an official extension applied to that period, use the extended date rather than the ordinary date.
Use the return period, not the filing date, to establish the deadline
For a monthly filer, the relevant deadline is the one assigned to that month’s GSTR-3B. Quarterly and special-category filers may have a different schedule. A return filed on the date shown as due is not late merely because it is near the end of the day; a return submitted after the applicable deadline can be late even if the tax was paid earlier.
Keep evidence of an extension
Save the notification or portal communication supporting any extended due date. The date affects both the number of late-fee days and the point from which section 50(2) interest is counted. If the dashboard and an older calendar or internal compliance sheet conflict, investigate the period-specific official instruction before calculating.
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How late fee is determined
The CGST Act’s general section 47(1) wording refers to ₹100 per day and a maximum of ₹5,000 for the specified delayed filings. That wording is not a complete answer for every GSTR-3B. Reduced amounts, caps, exemptions and waivers have been introduced through later notifications and may vary by return period and taxpayer class.
Historical GSTR-3B figures reported by CBIC
A CBIC GST status publication from 2019 described the reduced GSTR-3B late fee in force from October 2017 as:
| Return’s tax-liability status | Historical daily amount reported by CBIC | What the figure does not establish |
|---|---|---|
| Nil tax liability | ₹20 per day | It does not establish every current cap, waiver or later-period rule. |
| Non-nil tax liability | ₹50 per day | It does not establish the amount payable for every taxpayer category or period today. |
Use these numbers as historical context, not as a universal current rate. Before filing, identify the notification applicable to your return period and taxpayer category. The official material reviewed does not provide one complete current table covering every category, period, cap and waiver, so quoting a single amount without that check can overstate or understate the liability.
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Late-fee day count
Once the applicable daily amount and any cap are established, count the days from the day after the due date through the date the return is furnished, subject to the governing rule. Apply the notification’s nil or non-nil test and any statutory or notified ceiling. If a waiver covers particular days or periods, remove those days only as the waiver specifies.
Illustrative method: if a notification applicable to a particular filer sets a daily fee of ₹50 and the return is 4 eligible days late, the unadjusted fee is ₹50 × 4 = ₹200. A real calculation still requires the period’s cap, waiver and category rules.
When interest applies under section 50
Interest is tied to unpaid tax, not simply to the act of filing a return late. Section 50(1) states that a person who fails to pay tax within the prescribed period must pay interest for the period the tax remains unpaid. The statute says the rate notified by the government cannot exceed 18% under subsection (1); the rate applicable to your period must be checked in the relevant notification.
“Every person who is liable to pay tax in accordance with the provisions of this Act or the rules made thereunder, but fails to pay the tax or any part thereof to the Government within the period prescribed, shall for the period for which the tax or any part thereof remains unpaid, pay, on his own, interest at such rate, not exceeding eighteen per cent., as may be notified by the Government on the recommendations of the Council.”
Section 50(1), CGST Act, 2017
Section 50(2) provides that the calculation begins on the day after the date on which the tax was due. End the count when the tax is actually discharged in the manner relevant to the liability. A late filing date alone does not prove that the entire tax amount was unpaid for the same number of days.
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- The return period and its actual, including extended, due date.
- The tax amount that was payable and the portion that remained unpaid.
- The date and nature of the debit or payment that discharged the tax.
- The notified interest rate for that period and liability.
- For tax periods from January 2026, the minimum ECL balance relevant under GSTN’s enhanced calculation.
Basic interest formula
For a straightforward case in which the whole relevant tax amount remains unpaid, the conceptual calculation is:
Interest = unpaid tax × applicable annual rate × number of delayed days ÷ 365
The rate must be expressed as a decimal for arithmetic. For example, if an applicable notification produces a hypothetical 18% rate, ₹100,000 remained unpaid for 5 days, and no ledger adjustment applied, the illustrative interest would be ₹100,000 × 0.18 × 5 ÷ 365, or approximately ₹246.58. This is a demonstration of the method, not a statement that 18% applies to every period.
January 2026 change: minimum Electronic Cash Ledger balance
For tax periods from January 2026, GSTN enhanced the Table 5.1 calculation for delayed GSTR-3B returns. The calculation accounts for the minimum balance available in the Electronic Cash Ledger from the return due date until the date of tax debit. GSTN publishes the formula as:
Interest = (Net Tax Liability – Minimum Cash Balance in ECL from due date to date of debit) × (Number of days delayed ÷ 365) × Applicable Interest Rate
The adjustment is based on the minimum balance over the specified interval, not simply the balance seen on one day. Review the ledger history for the whole period used by the system.
What “minimum cash balance” changes
If cash was already available in the ECL and stayed there, that amount can reduce the base used in the described GSTN computation. The benefit is limited to the minimum balance during the due-date-to-debit interval. It does not erase interest on tax that was never covered by the available balance, and it does not change the notified rate or the statutory starting date.
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GSTN’s minimum-interest warning
GSTN’s January 2026 advisory says: “The interest auto-populated in GSTR-3B is only the minimum interest that is required to be paid by the taxpayer.” Treat the system amount as a floor. If your records, the applicable notification or a legally required adjustment produce a higher amount, increase the figure rather than reducing it to the portal’s value.
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System-computed interest is auto-populated in Table 5.1 of the subsequent period’s GSTR-3B. The system-generated GSTR-3B PDF includes the calculation breakup, which is useful for reconciling the number to your own working papers.
Reported February 2026 calculation issue
In an advisory dated 6 March 2026, GSTN reported that some taxpayers saw February 2026 interest in their March returns calculated without the minimum-cash-balance benefit. GSTN directed affected taxpayers to use the “RE-COMPUTE INTEREST” option and review the updated system-generated PDF. This instruction addresses the reported dated issue; it is not a finding that every portal calculation is incorrect.
Portal review sequence
- Open the return dashboard and select the exact tax period.
- Confirm the due date shown for that period and check whether an extension applies.
- Review the tax liability and identify the date on which the relevant tax was debited or paid.
- For January 2026 onward periods, examine the ECL balance from the due date through the debit date and identify the minimum balance.
- Check the applicable notified interest rate instead of substituting the section 50(1) ceiling.
- Open Table 5.1 and download the system-generated GSTR-3B PDF.
- If the figures resemble the March 2026 issue or otherwise conflict with your ledger, select “RE-COMPUTE INTEREST” when available, then download and review the revised PDF.
- Self-assess any amount above the system minimum and maintain the calculation supporting it.
Worked examples: keep the two liabilities separate
Example 1: late return, tax paid on time
Assume a hypothetical return was filed 3 eligible days after its due date, but the tax had already been discharged by the original payment deadline. The late-fee calculation uses the applicable daily fee and 3 eligible days. Because the tax was not unpaid after its due date, the facts do not automatically create interest for those 3 filing days. The return’s late submission and the tax-payment timing must be recorded separately.
Example 2: tax paid late and return filed late
Assume a hypothetical return was filed 6 days after its due date and the tax was debited 4 days after the tax-payment deadline. The late fee uses 6 eligible filing-delay days under the applicable fee notification. Interest uses the unpaid tax, the 4-day period beginning the day after the tax was due, the notified rate and any legally applicable ECL adjustment. Do not multiply the interest by 6 merely because the return was 6 days late.
Example 3: cash already in the ledger from January 2026
Assume the net tax liability is ₹200,000, the minimum ECL balance from the due date through debit is ₹80,000, the tax debit occurs 5 days late, and a hypothetical notified rate is 18%. Under GSTN’s published structure, the illustrative base is ₹120,000, producing ₹120,000 × 0.18 × 5 ÷ 365, or approximately ₹295.89. The actual result depends on the portal’s period data, the legally applicable rate and the exact ledger history.
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Common mistakes and how to fix them
Using ₹100 per day automatically
The ₹100-per-day and ₹5,000 figures are the general section 47(1) wording. GSTR-3B has had reduced amounts and subsequent notifications. Fix: retrieve the notification for the period and category before finalising the fee.
Using the historical ₹20 or ₹50 figure as a current guarantee
CBIC’s 2019 status document described those reduced amounts from October 2017, but it did not establish every later cap or waiver. Fix: treat the figures as historical context and verify the current rule.
Counting interest from the return filing date
Section 50(2) starts the statutory count on the day after tax was due. Fix: write down the tax due date and the tax debit date independently before counting days.
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Applying 18% without checking the notification
Section 50(1)’s 18% wording is a ceiling, not a universal operating rate. Fix: identify the notified rate for the relevant period and liability.
Assuming the portal amount is the final legal answer
GSTN describes its auto-populated interest as the minimum required. Fix: reconcile Table 5.1, the PDF, payment records and ECL history, and increase the amount if your self-assessment requires it.
Ignoring the ECL minimum balance
For periods from January 2026, failing to review the minimum balance can make a manual calculation higher than the GSTN formula where the adjustment is applicable. Fix: inspect the ledger continuously from the due date through the debit date, not just the closing balance.
Practical compliance checklist
- Identify the return period, filing frequency and taxpayer category.
- Capture the portal due date and any official extension.
- Record when the return was actually furnished.
- Locate the current late-fee notification, including nil-liability tests, caps, waivers and category rules.
- Determine the tax amount unpaid after its due date.
- Record the actual payment or tax-debit date.
- Apply section 50(2)’s day-after-due-date starting point.
- Use the notified interest rate, not the statutory maximum by default.
- For January 2026 onward periods, calculate the minimum ECL balance over the specified interval.
- Review Table 5.1 and the system-generated PDF.
- Use “RE-COMPUTE INTEREST” when the portal provides it and the displayed amount appears affected by the reported calculation issue.
- Pay and document late fee and interest as separate liabilities.
What a precise calculation still requires
No generic article can produce a final personal amount without the return period, applicable due date, tax-payment date, cash-ledger history, notified interest rate and current late-fee notification. Those inputs control the answer. If the liability is material, spans several periods, involves amended supplies or has conflicting portal records, preserve the ledger extracts, notifications and PDFs and obtain advice from a qualified Indian GST professional before filing.
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