The GST compliance calendar, and what missing one month actually costs

GST compliance is relentless rather than difficult. The same handful of filings come round every month, and the penalty structure is designed so that falling behind becomes progressively harder to escape.

The monthly cycle

• 11th — GSTR-1, details of outward supplies for the previous month. This is what populates your customers' GSTR-2B, so filing late directly delays their input credit.
• 20th — GSTR-3B, the summary return, with tax paid. For smaller taxpayers under QRMP the date is the 22nd or 24th, depending on the state.
• 13th — GSTR-5 and 6 where applicable; IFF for QRMP taxpayers who want their monthly invoices to reach customers without waiting for the quarter.
• 10th — GSTR-7 and 8 for TDS and TCS deductors.

Annually: GSTR-9 by 31 December, with GSTR-9C reconciliation where turnover exceeds ₹5 crore.

Why one missed month is not one problem

Returns must be filed in sequence. You cannot file August until July is filed. So a missed July blocks August, September and every month after it, while the late fee runs on each of them simultaneously.

Three months behind means three sets of fees accruing at once, and the e-way bill facility is blocked after two consecutive missed GSTR-3Bs — which for a goods business stops dispatch entirely.

What it costs

₹50 a day per return with tax or turnover, split equally between CGST and SGST, capped at ₹5,000 per return per Act. A nil return is ₹20 a day. Interest runs at 18% a year on tax paid in cash, and 24% where credit was wrongly claimed and used.

Work out the exact figure for a specific delay — the arithmetic is more alarming in aggregate than it looks per day.

The reconciliation that prevents most problems

Input tax credit is now available only where the supplier has filed and the invoice appears in your GSTR-2B. Claiming credit that is not in 2B is the single most common cause of a GST notice.

Reconcile 2B against your purchase register every month, before filing 3B — not at year end. Three things come out of it: invoices your supplier has not filed (chase them now, not in December), invoices you have not recorded, and amounts that differ. Each is cheap to fix in the same month and expensive to fix a year later.

A workable routine

1. 1st to 5th — close the previous month's sales and purchase registers.
2. 6th to 10th — download GSTR-2B, reconcile, chase missing supplier invoices.
3. 11th — file GSTR-1.
4. 15th to 18th — compute the liability, arrange the cash.
5. 20th — file GSTR-3B and pay.

Two points in that sequence are worth defending: the reconciliation before the 11th, and the cash arrangement before the 20th. Most failures are a cash problem presented as a filing problem — the return was not filed because the tax could not be paid, and the fee then accrues on top of a shortfall that was already the issue.

If you are already behind

File the oldest pending return first and work forward; nothing later can be filed until it is. File nil returns immediately where there was no activity, since those cost ₹20 a day rather than ₹50 and clear the sequence quickly. Where tax is genuinely unaffordable, filing the return still stops the late fee growing — interest on unpaid tax is considerably cheaper than a fee that runs daily on an unfiled return.