GST Interest Calculator
18% interest under Section 50 r/w Rule 88B — late GSTR-3B, short payment, and wrongly availed ITC.
What are you calculating?
Auto-fill due date
(editable — real dates drift with extensions)Head-wise details
Paid a supplier late — or not paid within 180 days?
That is a different computation — ITC reversal under Rule 37 rather than Rule 88B interest. Use the ITC Reversal & Interest on Supplier Payments beyond 180 Days tool — upload your ledger for a bill-wise working.
See worked examples
Late GSTR-3B — ₹296
Tax paid by cash ₹40,000, cash-ledger balance on due date ₹0, due 2026-07-20, filed 2026-08-04. Base ₹40,000 × 18% × 15/365 = ₹296.
Late GSTR-3B — Nil
Same as above but cash-ledger balance on due date ₹40,000 → base max(0, 40,000 − 40,000) = ₹0 → ₹0.
Wrong ITC — ₹1,134
ITC availed ₹50,000, credit-ledger fell below the availed amount (utilised) on 2026-03-10, reversed 2026-04-25. Base ₹50,000 × 18% × 46/365 = ₹1,134.
Disclaimer
This calculator computes interest under Section 50 of the CGST Act, 2017 read with Rule 88B of the CGST Rules, 2017 at 18% per annum on a simple-interest, actual-days basis. Results are indicative and depend on the accuracy of the data entered, applicable due-date extensions, and the facts of each case (including electronic cash/credit ledger balances). It does not constitute professional advice. For notices, demands, or disputed periods, consult a qualified GST professional — or contact us for expert support.
Key references: Sec. 16, 50, 47, 75(12), 128A CGST Act · Rule 88B CGST Rules · Ntf. 13/2017-CT, 09/2022-CT, 14/2022-CT, 12/2024-CT · Circular 192/04/2023-GST dt. 17.07.2023