IGST Calculator

IGST = Taxable value × GST rate ÷ 100

Taxable value (from inclusive) = Inclusive amount ÷ (1 + rate ÷ 100)

Place of supply, not the transporter's route, decides whether GST is IGST or CGST + SGST.

A Maharashtra business bills a Karnataka client ₹1,00,000 at 18%. IGST is ₹18,000 and the invoice total is ₹1,18,000.

IGST is a single levy at the full slab rate collected by the Centre and later apportioned to the consuming state. It applies whenever the supplier's location and the place of supply fall in different states or union territories, and also to imports, exports and supplies to or from special economic zones — categories the law treats as inter-state regardless of geography.

For e-commerce sellers this is the everyday case. A seller in Jaipur shipping to buyers across the country charges IGST on most orders, which keeps invoicing simple but makes the place-of-supply field on each order critical. For services, the default place of supply is the registered recipient's address, so a Bengaluru agency serving a Mumbai client bills IGST even though nothing physically moves.

IGST credit is the most flexible balance in the ledger: it can be used against IGST, then CGST, then SGST. Exporters who ship under payment of tax build up refundable IGST, while those using a Letter of Undertaking ship without tax and claim a refund of accumulated input credit instead.