How is GST interest calculated on delayed tax payments under Section 50?

Under the proviso to Section 50(1) of the CGST Act (retrospectively amended), interest @ 18% per annum is payable ONLY on the net tax liability paid by debiting the Electronic Cash Ledger (i.e. gross tax payable minus eligible Input Tax Credit). Interest is calculated on a daily basis from the day succeeding the statutory due date to the actual date of payment.

Is GST interest applicable if return is filed late but tax was already paid?

If cash was already deposited into the Electronic Cash Ledger on or before the due date, interest is not attracted on the portion of tax already deposited and available for discharge, as upheld by multiple High Courts and clarified under statutory GST provisions.

What is the penalty or late fee for delayed GSTR-3B filing?

Under Section 47 of the CGST Act, late fee is charged per day of delay (₹50/day for regular taxpayers, ₹20/day for Nil returns), subject to statutory capping limits based on aggregate turnover (₹500 for Nil returns, ₹2,000 to ₹10,000 for regular returns based on turnover slabs).

Tax & Compliance Tools

GST Interest Calculator Pro

Statutory Interest Calculation under Section 50 of CGST Act, 2017

Calculator Inputs

Enter your tax liability amount, statutory due date, actual payment date, and statutory interest rate.

Calculation Type

Single tax head or multi-head split (CGST, SGST, IGST & Cess)

Tax Head *

GST Payment / Liability Amount (₹) *

Original Statutory Due Date *

Actual Payment Date *

Annual Interest Rate (% p.a.) *

% per annum

Section 50(1): Interest on delayed payment of tax. Default calculator rate: 18% p.a., subject to applicable notification/law for the relevant period.

Section 50(2): Interest is calculated from the day succeeding the day on which the tax was due to be paid.

Section 50(3): For undue or excess claim of input tax credit / undue or excess reduction in output tax liability, use the applicable notified rate, with 24% p.a. as the current preset rate where applicable.

Calculation Output26 Days Delayed

Total Interest Liability

₹1,282.19

Net Tax Payable in Cash:₹1,00,000.00•Total Payable:₹1,01,282.19

Delay Days26

Interest Rate18%

Due Date20/08/2026

Net Tax₹1,00,000.00

Head-Wise Tax Breakdown

Sec 50(1) Proviso

Tax Head	Tax (₹)	Interest (₹)	Total (₹)
CGST	₹1,00,000.00	₹1,282.19	₹1,01,282.19
Total Statutory	₹1,00,000.00	₹1,282.19	₹1,01,282.19

GST Interest Calculator Pro

Statutory Interest Calculation under Section 50 of CGST Act, 2017

Total Interest Liability

₹1,282.1926 delay days @ 18% p.a.

Net Tax Payable

₹1,00,000.00

Total Payable Amount

₹1,01,282.19Tax + Interest Combined

Delay Days

26 Days20/08/2026 to 15/09/2026

Input Parameters & Statutory Assumptions

Original Due Date20/08/2026

Actual Payment Date15/09/2026

Applicable Interest Rate18% p.a.

Statutory ProvisionSection 50(1) CGST Act, 2017

1. Tax Head-Wise Statutory BreakdownCGST, SGST, IGST & Cess Apportionment

Tax Head	Tax Amount (₹)	Interest Amount (₹)	Total Payable (₹)
CGST	₹1,00,000.00	₹1,282.19	₹1,01,282.19
TOTAL STATUTORY PAYABLE	₹1,00,000.00	₹1,282.19	₹1,01,282.19

2. Statutory Interest Calculation FormulaDeterministic Section 50 Formula Representation

• Applied Formula: Interest = (Tax Amount × 18% × 26 Days) ÷ (365 × 100) [As per Section 50 of CGST Act, 2017]

• Day Count Computation: Day succeeding due date (20/08/2026) to payment date (15/09/2026) = 26 calendar days inclusive.

Statutory References & Legal Context

• Under Section 50(1) proviso, interest is charged @ 18% p.a. only on the net tax liability paid through Electronic Cash Ledger.

• Section 50(2): Interest is calculated from the day succeeding the day on which tax was due.

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Statutory Legal Disclaimer • SKM Laws And Associates: This report is generated for statutory estimation and compliance review based on the applicable provisions of Section 50 of the CGST Act, 2017. For departmental notice defense and advisory, consult SKM Laws And Associates.

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Calculations provide indicative statutory estimates. For departmental filings, notice resolution, and custom tax planning, consult directly with SKM LAWS AND ASSOCIATES.

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