CGST, SGST or IGST: how GST applies to your invoices

One of the most common questions Indian businesses ask about GST is simple to state and easy to get wrong: should this invoice charge CGST and SGST, or IGST? The answer comes down to the place of supply.

Intra-state supply: CGST + SGST

When the supplier and the place of supply are in the same state, GST is split into two equal halves: Central GST (CGST) and State GST (SGST). For example, an 18% rate becomes 9% CGST plus 9% SGST. Both appear as separate lines on the invoice.

Inter-state supply: IGST

When the supply crosses state lines, a single Integrated GST (IGST) applies at the full rate — 18% in the example above. IGST also applies to imports and to supplies to and from Special Economic Zones.

Why it matters

Charging the wrong combination creates mismatches that ripple into your GST returns and your customer's input tax credit — a frequent source of notices and reconciliation headaches. Because the correct split depends on state codes and the place-of-supply rules, it's exactly the kind of thing software should handle for you.

• Same state → CGST + SGST
• Different states → IGST
• The place of supply, not just the billing address, drives the choice

In SoarLedger, the CGST/SGST vs IGST decision is made automatically from the place of supply, so your invoices are correct the first time and your returns line up.