Complete GST Guide for SMEs in 2025

Eight years after rollout, GST is still the single biggest source of compliance anxiety for Indian SMEs. The rules have stabilised, but the operational details — e-invoicing thresholds, ITC matching, e-way bill rules — keep evolving. Here's the 2025 baseline every owner should know.

The thresholds that matter

**Registration:** ₹40 lakh for goods, ₹20 lakh for services (₹20/10 lakh in special-category states).

**Composition scheme:** Up to ₹1.5 crore turnover for goods, ₹50 lakh for services. 1% / 5% / 6% rates.

**E-invoicing:** Mandatory for businesses above ₹5 crore aggregate turnover.

**E-way bill:** Required for inter-state movement of goods above ₹50,000.

The monthly rhythm

By 11th — File GSTR-1 (outward supplies) for the previous month.

By 13th — IFF for QRMP filers.

By 20th — File GSTR-3B and pay tax liability.

Continuous — Reconcile GSTR-2B with purchase register before claiming ITC.

Missing a deadline costs ₹50 per day plus interest. Worse, mismatched ITC claims trigger notices that take months to resolve.

The five common mistakes

Claiming ITC without matching GSTR-2B.

Wrong HSN/SAC codes on invoices above ₹5 crore turnover.

E-way bill generated after the truck has left.

Missing reverse charge entries on freight and legal fees.

Forgetting to file NIL returns when there is no activity.

How automation changes the game

With InventorySaaS, your sales invoices auto-flow into GSTR-1, IRN is generated at the point of billing, and the 2B reconciliation runs every morning. Most customers cut their compliance work from 2 days a month to under 2 hours.

Next steps

Audit your last three months of returns. If your ITC claim doesn't reconcile to within 1% of your 2B, that is your first project.