Missing a GST due date is one of the most avoidable ways a business ends up with late fees and interest. The dates themselves aren't complicated once you know your filing frequency — the confusion usually comes from mixing up the monthly and quarterly (QRMP) schedules, or forgetting that GSTR-3B can't be filed until every prior period is cleared.
This is the calendar we hand new clients in their first week, before we've even set up their bookkeeping. Print it, pin it, or better still, set calendar reminders three days before each date so a slow bank transfer or a public holiday doesn't turn a planned payment into a late one.
Monthly Filers
- GSTR-1 (outward supplies): 11th of the following month
- GSTR-3B (summary return with payment): 20th of the following month
If your turnover is above ₹5 crore, you're required to be a monthly filer regardless of preference — QRMP isn't available to you. Below that threshold, monthly filing is still the default unless you've actively opted into QRMP.
QRMP Scheme Filers (Turnover Up To ₹5 Crore)
- IFF, Invoice Furnishing Facility (optional, for the first two months of the quarter): 13th of the following month
- PMT-06 (monthly tax payment, months 1 and 2 of the quarter): 25th of the following month
- GSTR-1 and GSTR-3B: filed quarterly, due by the 13th and 22nd/24th respectively — the exact date depends on which state group your principal place of business falls under (Category X states file by the 22nd, Category Y states by the 24th)
The IFF is worth using even though it's optional: it lets your B2B buyers see specific invoices in their GSTR-2B a month earlier than waiting for your full quarterly GSTR-1, which keeps supplier relationships smoother and avoids the "why isn't this in my 2B yet" conversation.
Other Recurring Dates Businesses Forget
- CMP-08 (composition scheme, quarterly statement-cum-challan): 18th of the month after quarter end
- GSTR-4 (composition scheme annual return): 30th April
- GSTR-9 (annual return, regular taxpayers above the notified turnover threshold): 31st December following the financial year
- GSTR-9C (reconciliation statement, required above ₹5 crore turnover): filed alongside GSTR-9, same deadline
A Simple Rule That Covers Almost Everyone
Regardless of scheme, treat the 20th of every month as your hard deadline — that's when GSTR-3B and its tax payment fall for monthly filers, and it's also effectively when QRMP filers need their PMT-06 sorted for the relevant month (25th for QRMP specifically, but keeping the same mental discipline every month prevents drift). QRMP shifts the return filing to quarterly while keeping the tax payment obligation monthly — a distinction that trips up more businesses than any other part of the scheme.
What a Missed Date Actually Costs
A late GSTR-3B attracts a late fee of ₹50 per day (₹25 CGST + ₹25 SGST) for a return with tax liability, or ₹20 per day for a nil return, capped by your turnover slab. On top of that, 18% per annum interest accrues on any tax paid after the due date, calculated day-by-day from the due date until actual payment. Beyond the direct cost, GSTR-3B for a period can't be filed until every earlier period's GSTR-3B has been filed — so a single missed month, left unaddressed, can quietly compound into a filing backlog that blocks you from filing anything current.
If You're Consistently Cutting It Close
A good early-warning habit is closing your books weekly rather than monthly — that turns the return itself into a five-minute confirmation of numbers you already know, rather than a data-entry exercise crammed into the days before the deadline. That's exactly the gap our monthly retainer plans close for clients who'd rather not think about this every month; a dedicated bookkeeper keeping your ledger current all month means the 20th is never a scramble.
Frequently Asked Questions
Can I switch from monthly filing to QRMP mid-year? Yes — you can opt into or out of QRMP at the start of any quarter, provided your aggregate turnover in the preceding financial year was up to ₹5 crore. The window to change usually opens on the GST portal in the first month of the new quarter.
What happens if the due date falls on a Sunday or public holiday? Unlike some tax deadlines, GST due dates are not automatically extended for weekends or holidays unless the government issues a specific notification. Don't assume an extension — file on or before the stated date.
Does nil filing still require action on every due date? Yes. A nil GSTR-3B or GSTR-1 still needs to be filed by the due date even if there's genuinely nothing to report — skipping it because "there's nothing to file" still triggers the late fee.