Pick the return, the due date and the date you actually filed, and this works out the late fee and the interest. Both are charged separately and people usually budget for only one of them.
The fee runs from the day after the due date until the day you file.
There is a maximum, and it is based on turnover: ₹500 per return for a nil return, and a turnover-linked cap above that. The cap is the reason a return that is six months late often costs far less than the daily rate would suggest — but it is also why people leave them, and the interest keeps running regardless.
Interest is charged at 18% per annum on the tax paid late, calculated day by day from the due date. It applies to the cash portion of your liability — the part you actually had to pay, not the part settled from input credit.
Unlike the late fee, interest has no cap. A large liability left unpaid for a year costs 18% of it, on top of the fee.
The arithmetic is: tax × 18% × days ÷ 365.
The fee and the interest are the visible part. Two quieter costs usually hurt more.
First, your buyers. Your GSTR-1 is what puts their input credit in their GSTR-2B, so a late return holds up their claim and they will hear about it from their own accountant before they hear about it from you.
Second, continued default can lead to the e-way bill facility being blocked, which stops goods moving — a far more expensive problem than the fee that caused it.
A month with no sales is not a month with no obligation. A nil GSTR-3B that is never filed collects ₹20 a day, and — more expensively — blocks the next month's return, because GST returns must be filed in order.
That is how a business with no trading activity ends up with a year of stacked late fees over returns that would each have taken thirty seconds.
Yes — ₹20 a day, split between CGST and SGST, capped at ₹500 for that return. It is smaller than the normal fee but it is not zero.
Only through an amnesty scheme, which the government announces from time to time for specific periods. There is no routine waiver on request.
Interest applies to the amount discharged in cash. The portion set off against available input tax credit is generally outside it, which is why the cash figure is the one that matters here.
You cannot. Returns must be filed in sequence, so a missed month blocks every month after it and the fees accumulate on each until the backlog is cleared.