GST Calculator (India)

GST (Goods and Services Tax) is India's unified indirect tax introduced on 1 July 2017, replacing a complex web of central and state taxes including VAT, service tax, excise duty, and luxury tax. It applies to virtually every business transaction in India — from buying a coffee at a café to invoicing a software project to a foreign client.

GST is structured as a destination-based tax with three components depending on whether the transaction is within or across states.

CGST (Central GST) — the central government's share. Charged on intra-state transactions. Half the GST rate goes to CGST.

SGST (State GST) — the state government's share. Charged on intra-state transactions. The other half of the GST rate.

IGST (Integrated GST) — charged on inter-state transactions. The full GST rate goes to IGST, which is later distributed between centre and states.

For example, an 18% GST on an intra-state transaction is split as 9% CGST + 9% SGST. The same 18% on an inter-state transaction is charged entirely as IGST.

• 0% — Essential items: fresh milk, vegetables, books, education, healthcare
• 5% — Common goods: packaged food, footwear under ₹1,000, mass-use items
• 12% — Processed food, mobile phones, business class travel
• 18% — Standard rate: most goods and services including electronics, restaurants, software
• 28% — Luxury and sin goods: cars, ACs, tobacco, premium services
• 0.1% / 3% — Special rates: gold, diamonds, precious metals

Add GST (forward calculation): If a product costs ₹1,000 and GST is 18%, then GST = ₹180 and total payable = ₹1,180.

Remove GST (reverse calculation): If you paid ₹1,180 inclusive of 18% GST, the formula is: Net = Total ÷ (1 + GST%/100). So net = 1180 ÷ 1.18 = ₹1,000 and GST embedded = ₹180.

The reverse calculation is critical for shopkeepers and businesses generating GST-inclusive invoices, and for consumers verifying invoice components.