A day-wise GST interest calculator for section 50
This GST interest calculator works out interest under section 50 of the CGST Act for tax paid after its due date and for input tax credit that was wrongly availed and used. Add as many entries as you need — one per month, per tax head or per invoice — with the amount, the due date (or date the credit was used) and the date you paid or reversed it. It counts the days, applies 18% a year and totals everything, rounded to the rupee as section 170 requires.
Use it before paying through Form GST DRC-03, to check a notice, or to see what a late GSTR-3B will cost. The late fee for the return itself is a separate charge — see the GST late fee calculator. The rules were checked on 24 October 2026; the result is an estimate, not tax advice.
How to use the GST Interest Calculator (Section 50, Late Payment and ITC)
- For each amount, type a short description (for example “GSTR-3B July — CGST”).
- Choose the type: late tax under section 50(1) or wrongly used credit under section 50(3).
- Enter the amount, the due date (or the date the credit was used) and the date of payment or reversal.
- Add more entries with “Add entry”; keep the rates at 18% unless a notification says otherwise.
- Read the total, the day-wise working and the notes; download the CSV or copy the working for your records.
GST Interest Calculator (Section 50, Late Payment and ITC) features
Many entries at once
Up to 30 lines, each with its own dates, so a whole year of late payments fits in one sheet.
Both kinds of interest
Late payment of tax under s.50(1) and wrongly availed and utilised ITC under s.50(3).
Exact day count
From the day after the due date up to the payment date, divided by 365.
Rounded the official way
The total is rounded to the nearest rupee, as section 170 requires.
Ready for DRC-03
A CSV and a text working you can attach or paste when you pay voluntarily.
How GST interest is calculated
Interest = amount × 18% × days ÷ 365. A GSTR-3B for July 2026 was due on 20 August; if ₹1,20,000 of tax was paid in cash on 15 September, it was 26 days late and interest is ₹1,20,000 × 18% × 26/365 = ₹1,538.63. Credit of ₹40,000 wrongly availed and used on 20 May and reversed on 10 October adds 143 days: ₹2,820.82. Together ₹4,359.45, paid as ₹4,359.
| Situation | Section | Rate | Interest runs |
|---|---|---|---|
| Return filed late, tax paid in cash | 50(1) + proviso | 18% | Day after due date → date of cash debit |
| Tax short-paid, paid later | 50(1) | 18% | Due date → date of payment |
| ITC wrongly availed and used | 50(3) | 18% (24% before the 2022 change) | Date of use → date of reversal or payment |
| ITC wrongly availed but not used | — | Nil | Reverse the credit; no interest |
Rules that change the amount
- Only the cash portion of a late return carries interest; tax set off from your credit ledger does not (s.50(1) proviso, effective from 1 July 2017).
- Cash already sitting in your electronic cash ledger from the due date until it was used is left out (Rule 88B(1) proviso, inserted in July 2024).
- Credit is treated as used only when your credit-ledger balance falls below the wrongly availed amount, and only to the extent it falls — so enter that shortfall, not the whole credit.
- Interest must be paid in cash and for each head (CGST, SGST/UTGST, IGST) separately.
GST Interest Calculator (Section 50, Late Payment and ITC) FAQ
What is the GST interest rate for late payment?
18% a year under section 50(1), calculated day by day on the tax paid late, as notified in Notification 13/2017-Central Tax.
Is interest on wrong ITC 24% or 18%?
The Act allows up to 24%, and 24% was notified in 2017, but the Finance Act, 2022 replaced it with 18% with effect from 1 July 2017. So 18% applies, and only if the wrong credit was actually used.
How do I use this as a GST interest calculator for DRC-03?
Add one entry per head and period, then copy the working or download the CSV. In DRC-03 choose “voluntary” as the cause and enter the interest under each head.
Is interest charged on the gross tax or the net cash liability?
On the net tax paid in cash when a return is filed late. Interest on the gross amount applies only where tax is paid after proceedings under sections 73, 74 or 74A have started.
Does the GST portal calculate interest automatically?
For a late GSTR-3B the portal computes interest on the cash portion and shows it in the next return. Use this calculator to check it, or for amounts paid outside the return.
Is my data sent anywhere?
No. The GST interest calculator runs in your browser; nothing you type leaves your device.