GST has been with us since July 2017. Every year brings minor rate tweaks, notification corrections, and a round of rumours about slab consolidation. In 2026 the structure is stable: five main rates — 0%, 5%, 12%, 18% and 28% — plus special rates of 0.1% and 3% for specific categories like gold and certain exports.
Where the confusion lives
The real cost to businesses is not the headline rate. It is in three places:
- Rate-boundary items — apparel at MRP ₹1,000 versus ₹1,001, restaurants in a five-star property versus a non-star property, or prepared food versus "food sold in the premises of an eating joint". Getting the category right is cheaper than defending it in assessment.
- Input tax credit on blocked items — section 17(5) blocks ITC on items like motor vehicles below 13 seats, club memberships, employee health and life insurance (with specific exceptions), and works contracts for immovable property. Every year we see ITC claimed on at least one of these in new clients' books.
- Reverse charge under 9(3) and 9(4) — on goods transport agencies, legal services, director sitting fees, import of services, and notified categories of goods. RCM GST has to be paid in cash, and the ITC can only be claimed after the cash payment is made.
Monthly compliance cadence
For a regular monthly taxpayer with a single GSTIN, the rhythm is:
- 10th — GSTR-7 (TDS) and GSTR-8 (TCS) filings for deductors and e-commerce operators.
- 11th — GSTR-1 outward supplies return. Missing this by even a day exposes your customers to ITC mismatch.
- 13th — Invoice Furnishing Facility (IFF) for QRMP taxpayers.
- 20th — GSTR-3B summary return, along with tax payment. Late payment attracts interest at 18% per annum.
What changes for smaller businesses
If your aggregate turnover was up to ₹5 crore in the previous year, you can opt for QRMP — quarterly returns with monthly payment. This reduces filings from 24 to 12 a year for a single GSTIN, but monthly tax payment is still required by the 25th using either the fixed-sum method or self-assessment.
E-invoicing checklist
Businesses with aggregate turnover above ₹5 crore in any financial year since 2017-18 must generate an Invoice Reference Number (IRN) on the Invoice Registration Portal for every B2B invoice. The IRN has to appear on the printed invoice. If your billing tool does not connect to the IRP, you need a GSP/ASP in between.
Three mistakes we fix regularly
- Claiming ITC on vendor invoices that do not appear in GSTR-2B — now a compliance failure, not just a timing difference.
- Filing GSTR-3B before reconciling with GSTR-2B — leads to either excess ITC that must be reversed later, or missed ITC that is hard to recover.
- Ignoring e-way bill expiry when goods are held up in transit — the bill must be extended before expiry, not after.
Getting ready for the next assessment
GST assessments are now largely system-driven — DRC-01B for liability mismatch, DRC-01C for ITC mismatch, and ASMT-10 for transaction-level scrutiny. The way through all three is the same: monthly reconciliation before filing, not six months later.