GST compliance is predictable once you establish a monthly rhythm. The most common cause of penalties isn't ignorance — it's treating filing as a last-minute task. Here is the complete GST return calendar and a workflow to stay penalty-free.
Monthly GST Return Due Dates (FY 2025–26)
| Return | Who Files | Due Date |
|---|
| GSTR-1 (monthly) | Registered businesses with turnover > ₹5 crore | 11th of following month |
| GSTR-1 (QRMP) | Turnover ≤ ₹5 crore (opted for QRMP) | 13th of following quarter |
| IFF (Invoice Furnishing Facility) | QRMP filers — upload B2B invoices monthly | 13th of following month |
| GSTR-3B (monthly) | Turnover > ₹5 crore | 20th of following month |
| GSTR-3B (QRMP) | Turnover ≤ ₹5 crore | 22nd/24th (state-wise) of following quarter |
| GSTR-9 (Annual) | All registered (turnover > ₹2 crore mandatory) | 31 December 2026 |
| GSTR-9C (Reconciliation) | Turnover > ₹5 crore — CA certified | 31 December 2026 |
Late Fee for GST Returns
| Return | Late Fee | Maximum Cap |
|---|
| GSTR-1 | ₹50/day (₹20/day NIL return) | ₹10,000 |
| GSTR-3B | ₹50/day (₹20/day NIL return) | ₹10,000 |
| GSTR-9 | ₹200/day | 0.25% of turnover |
A Lightweight Monthly GST Workflow
- Week 1: Collect all sales invoices. Upload to accounting software. Reconcile with GSTR-2B.
- Week 2: Reconcile purchase invoices with GSTR-2B. Flag mismatches with vendors.
- Week 3: Compute ITC eligible. Review blocked credits (Section 17(5)).
- Week 4 (before 11th): File GSTR-1. Before 20th: File GSTR-3B with tax payment.
- Monthly: Save all filing acknowledgements. Maintain Input Register.
Common GST Mistakes to Avoid
- Claiming ITC without invoice match in GSTR-2B — leads to demand + interest
- Not reconciling GSTR-2B with books monthly — causes annual GSTR-9 nightmares
- Blocking credits on wrong basis — know the Section 17(5) blocked credit list
- Not filing NIL returns on time — still attracts ₹20/day late fee
- Missing RCM (Reverse Charge Mechanism) on imports, GTA, legal fees, etc.
