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GST Interest Calculator

Estimate Indian GST interest for the path that matches your event — 18% or 24% — then re-check the portal before you treat any figure as filing-ready. Separate from the Section 47 late fee.

Calculation path

Default path: Section 50(1) and Rule 88B(1) interest on the chargeable cash portion.

Optional: enter the actual amount and qualifying minimum ECL balance for each tax head. The calculator uses exactly what you enter; it never invents a CGST/SGST split.

Enter the tax payable through the Electronic Cash Ledger for this delayed return.

Enter the lowest eligible Electronic Cash Ledger balance from the due date until debit/offset.

Enter the official due date that applies to this return.

Enter the calendar date on which the cash liability was debited or offset.

Total Interest

Enter all four inputs to see the ordinary delayed-return estimate.

Assumption: This estimate uses the ordinary delayed-return path in Section 50(1) and Rule 88B(1), a 365-day year, and the calendar dates entered above.

Before filing or paying: This is an estimate, not a GST Portal liability or tax advice. Check the applicable notification and portal result.

What does ordinary delayed-return interest look like?

One takeaway: for a late return paid from cash, interest is usually 18% a year on the cash amount not already covered by a qualifying ECL balance. Why the path matters: three Section 50 situations use different inputs and rates. Mixing them invents the wrong principal. Pick the wrong path and you can: - Apply 24% when only 18% fits - Subtract ECL on a path that does not allow it - Count days from the wrong starting date Do it right and you get: - The matching rate (18% or 24%) - A principal the selected rule actually uses - Calendar-day interest you can re-check against the portal

Rule 88B(1) estimate formula

Interest = (Net cash liability − qualifying minimum ECL balance) × 18% × delay days / 365
Rates on this page: - Ordinary delayed return and other unpaid or short-paid tax → 18% p.a. - Wrongly availed and utilised ITC → 24% p.a. Mere ITC availment without utilisation is outside the 24% path.

Is this interest or a late fee?

Interest under Section 50 is for delayed payment of tax. Late fee under Section 47 applies when a GST return is filed late. Use the dedicated GST Late Fee Calculator for that filing task.
Use GST Late Fee Calculator

Choose a path

Which Section 50 interest path fits?

Start from the event, not the rate. Select a card to switch the calculator above.

Each card selects the matching calculator path. The cards do not decide whether a legal condition applies to your facts.

Two paths can both use 18%. The inputs and ECL rule still differ — choose from the event and dates.

Illustrative scenarios

Can I reproduce the result?

Three worked examples. Select one to switch the calculator path, then enter the listed values.

Illustrative scenarios, not customer results. Confirm your official dates, tax heads, notifications, and facts before filing or paying.

01

What if a delayed return still had ECL cover?

A return is filed after its due date. Cash payment is ₹100,000, and a qualifying minimum ECL balance of ₹30,000 sits through the period.

Inputs

Path: Ordinary delayed return Net cash liability: ₹100,000 Qualifying minimum ECL balance: ₹30,000 Due date: 2026-02-20 Debit or offset date: 2026-03-15

Output

Chargeable principal: ₹70,000. 23 days × 18% / 365 gives total interest of ₹793.97.

Why this result
Qualifying ECL reduces the cash principal by ₹30,000 — never below zero.
What it means
You see the ECL effect separately from the tax amount.
Where it stops
Rule 88B(1) delayed-return path only. A special notification, proceeding, or portal treatment can change the liability.

Use the lowest eligible ECL balance in the period, not an assumed closing balance.

Select this path in the calculator
02

What if ITC was wrongly availed and utilised?

ITC of ₹100,000 was both wrongly availed and used to pay output tax, then reversed or paid 23 calendar days later.

Inputs

Path: Wrongly availed and utilised ITC Amount both wrongly availed and utilised: ₹100,000 ITC utilisation date: 2026-02-20 ITC reversal or tax payment date: 2026-03-15

Output

Chargeable principal: ₹100,000. 23 days × 24% / 365 gives total interest of ₹1,512.33.

Why this result
24% applies only to the amount both wrongly availed and utilised.
What it means
No ECL deduction here — the full entered amount stays chargeable.
Where it stops
This does not decide whether ITC was wrongly availed or utilised. Those are legal and factual questions outside the calculator.

Separate mere availment from credit actually used to pay output tax before choosing this path.

Select this path in the calculator
03

What if other tax was unpaid with no ECL shortcut?

Other unpaid or short-paid tax of ₹100,000 is paid 23 calendar days after its applicable due date.

Inputs

Path: Other unpaid or short-paid tax Other unpaid or short-paid tax: ₹100,000 Applicable due date: 2026-02-20 Actual payment date: 2026-03-15

Output

Chargeable principal: ₹100,000. 23 days × 18% / 365 gives total interest of ₹1,134.25.

Why this result
Rule 88B(2) uses the unpaid or short-paid tax amount and skips the delayed-return ECL adjustment.
What it means
A cash-ledger balance from another situation does not reduce this estimate.
Where it stops
Proceedings, prior-period declarations, special notifications, and case facts can change the final liability.

Choose from the event and dates, not the rate alone — two paths can share 18% with different inputs.

Select this path in the calculator

What should you enter and check next?

Enter the amount and calendar dates for the selected path. The result shows chargeable principal, rate, days, daily interest, and total interest. Before filing or paying, compare with the applicable notification and GST Portal calculation. This page does not decide extensions, waivers, proceedings, historical-period treatment, or portal-specific adjustments.

Is this a late fee instead?

Section 50 interest concerns delayed payment of GST. Section 47 late fee concerns filing a return after its due date. This calculator does not combine the two amounts.
Use GST Late Fee Calculator

Where can I check the rules?

The calculator and examples use the provisions below. Open the source that matches your path and tax period before relying on an estimate.

Rules reviewed: July 31, 2026.

Estimate and general information only. This is not a GST Portal liability, filing, tax, or legal advice.

GST Interest Calculation FAQ

Q1.Does this calculator cover every Section 50 interest path?

No. It covers three chargeable paths: - Ordinary delayed returns → 18% - Other unpaid or short-paid tax → 18% - ITC both wrongly availed and utilised → 24% Other Section 50 situations can need extra facts outside this page.

Q2.How does Electronic Cash Ledger balance change ordinary delayed-return interest?

On the ordinary delayed-return path only, the calculator subtracts the qualifying minimum ECL balance from net cash liability — never below zero. It does not move balances between tax heads in the detailed report.

Q3.How does the calculator count interest days?

It uses the calendar-day difference between the two dates for the selected path. A payment, reversal, or debit on or before the starting date produces a zero-interest result for that period.

Q4.Can I enter separate CGST, SGST, IGST, and cess amounts?

Yes. Turn on the detailed tax-head report and enter each applicable amount. - Heads stay separate - No invented CGST/SGST split - On the ordinary path, any ECL adjustment stays inside the same head

Q5.Is this result the same as the GST Portal liability?

No. This is a general estimate from the values you enter. The GST Portal, notifications, proceedings, historical-period declarations, and case facts can produce a different liability. Check the portal and the applicable law before filing or paying.

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Disclaimer: This tool provides arithmetic for one GST rate at a time, not tax, legal or filing advice. Check the original transaction's rate, rounding, exemptions, invoice requirements and filing rules before using a result for an invoice or return.