GST interest
18% a year on the net cash liability, counted from the day after the due date to the day the tax was paid.
Interest runs on the tax settled from the cash ledger, not on the gross liability.
Not the gross output tax — only what was settled in cash.
Optional. Fill it in to see what the proviso saves.
Interest
₹789.04
| Tax paid from the cash ledger | ₹1,00,000.00 |
|---|---|
| Rate | 18% a year |
| Days of delayCounted from the day after the due date, on a 365-day year. | 16 |
| Interest | ₹789.04 |
| Rounded to the rupee | ₹789 |
How this worksShow
Interest runs on the cash, not on the tax
This is the whole reason to use a calculator rather than a mental multiplication. Interest under section 50 is charged on the part of the liability discharged by debiting the electronic cash ledger — not on the gross output tax for the period. Tax settled from input credit carries none.
The gap is not small. A business with ₹5,00,000 of output tax and ₹4,00,000 of credit pays interest on ₹1,00,000: thirty days late, that is ₹1,479.45 rather than ₹7,397.26. Five times over, on an ordinary set of figures.
| Rule | Figure | Statutory basis |
|---|---|---|
| Tax paid after the due date | 18% a year | s.50(1), CGST Act 2017 |
| What interest is charged on | the cash leg | Proviso to s.50(1) read with Rule 88B(1), CGST Rules 2017 |
| Credit wrongly availed and used | 24% a year | s.50(3) read with Rule 88B(3), CGST Rules 2017 |
| Period | day after the due date to payment | Rule 88B, CGST Rules 2017 |
| Where proceedings have begun | gross liability | Proviso to s.50(1), CGST Act 2017 |
Counting the days, and the leap year
Interest runs from the day after the due date through the day of payment, both counted. A return due on 20 August and paid on 5 September is sixteen days late, not fifteen.
- The statute says “per annum” and settles nothing about the divisor. This page uses 365 days, which is what the portal’s own computation does.
- It uses 365 even where the period spans 29 February. A divisor that changed with the calendar would give two different answers for the same delay with nothing on screen to say why.
- Filing on the due date produces nil, not one day.
| Rule | Figure | Statutory basis |
|---|---|---|
| Day count divisor | 365 | s.50, CGST Act 2017 |
What the page assumes
That the return has been filed and the cash-ledger concession applies. Where proceedings under section 73 or 74 have already been begun, interest reverts to the gross liability, and the figure here understates it — the calculator shows the gross comparison for exactly that reason. ComplyADI tracks the cash and credit legs from the returns themselves, so the base is the one your ledger actually produced.
Rates and thresholds as at 10 September 2026. This page is an estimate, not professional advice, and it is not a filing.
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Stop calculating by hand
ComplyADI does this on your own books
This page works one figure at a time. ComplyADI reads your ledgers, applies the same rules across every transaction, and shows you what is due before the date rather than after it.