GST — registration, returns and reconciliation basics

GST registration may be compulsory in certain cases irrespective of turnover, such as specified inter-state supplies, persons liable under reverse charge, casual taxable persons, non-resident taxable persons, and suppliers through e-commerce operators where applicable GST provisions require registration. Otherwise it becomes mandatory once your aggregate turnover crosses the prescribed threshold.

• Goods: generally ₹40 lakh turnover (₹20 lakh in special category states)
• Services: generally ₹20 lakh turnover (₹10 lakh in special category states)
• Specified categories (e.g. certain inter-state supplies, reverse charge, casual / non-resident taxable persons, supplies via e-commerce operators) — registration may be required irrespective of turnover, subject to the applicable GST provisions
• Voluntary registration is allowed and often useful for B2B businesses

Most businesses file GSTR-1 (outward supplies) and GSTR-3B (summary + tax payment). QRMP scheme allows quarterly returns with monthly tax payment for small taxpayers.

• GSTR-1 — outward supplies (monthly or quarterly under QRMP)
• GSTR-3B — summary return with tax payment
• GSTR-9 / 9C — annual return and reconciliation (turnover-based)
• CMP-08 / GSTR-4 — for composition scheme dealers

Input Tax Credit is allowed only if it appears in GSTR-2B (auto-populated from your suppliers' GSTR-1). Mismatch between purchase register and GSTR-2B is a leading cause of notices and ITC denial.

• Reconcile GSTR-2B vs purchase register every month
• Follow up with vendors who haven't filed GSTR-1
• Avoid claiming ITC without invoice or supplier filing

E-way bill is required for movement of goods above the threshold value. E-invoice (IRN) is required for B2B invoices once your turnover crosses the prescribed limit.

Most GST notices arise from preventable issues. Knowing these early avoids penalty and interest.

• GSTR-1 vs GSTR-3B mismatch
• GSTR-3B vs GSTR-2B ITC mismatch
• Non-filing or late filing of returns
• Mismatch with income tax / TDS data