GST calculator

What is GST?

India's Goods and Services Tax (GST) is a value-added tax charged on most goods and services at slab rates of 5, 12, 18 or 28 percent. This calculator adds GST on top of a base amount or removes it from a GST-inclusive total, and shows the split that every Indian invoice needs. Within a single state the tax divides equally into CGST and SGST, each half the rate; across state lines it is charged as a single IGST at the full rate. For example, 1,000 rupees at 18 percent becomes 1,180: either 90 CGST plus 90 SGST inside a state, or 180 IGST between states. Enter an amount, pick a rate, and choose add or remove to see the base, the tax and the total. Everything runs in your browser, so nothing you enter is sent to a server.

Key facts

• To add GST, the tax equals base times rate divided by 100, so 10,000 at 18 percent GST is 1,800 tax and an 11,800 total.
• To remove GST from an inclusive amount, base equals total divided by (1 plus rate/100), so 1,180 at 18 percent gives a 1,000 base and 180 GST.
• For a supply within the same state, GST splits equally into CGST and SGST, each half the rate, while an inter-state supply is charged as IGST at the full rate.
• GST in India has several slabs: 0, 5, 12, 18 and 28 percent, plus 3 percent for specific items, determined by the goods' HSN code or the service's SAC code.
• Under the reverse-charge mechanism the recipient, not the supplier, pays GST directly to the government on certain notified supplies.

Glossary

GST (Goods and Services Tax)

GST is India's value-added tax on the supply of goods and services, charged at slab rates of 0, 5, 12, 18 and 28 percent (plus 3 percent for specific items), with the rate set by classification.

CGST and SGST

CGST (Central GST) and SGST (State GST) are the two halves of the tax on an intra-state supply. Each is charged at half the total rate, so 18 percent within a state is 9 percent CGST plus 9 percent SGST.

IGST

IGST (Integrated GST) is the single tax charged on an inter-state supply, levied at the full rate instead of being split into CGST and SGST. An 18 percent inter-state supply is 18 percent IGST.

HSN and SAC codes

An HSN code classifies goods and a SAC code classifies services, and each code maps to a specific GST slab. The correct code determines the rate to apply on an invoice.

Reverse charge (RCM)

Under the reverse-charge mechanism, the recipient rather than the supplier pays GST directly to the government on certain notified supplies. A normal forward calculation does not apply where RCM is in effect.

Add vs remove GST

Adding GST treats a figure as the base and puts tax on top: GST = base x rate / 100. Removing GST treats a figure as the inclusive total and works backwards: base = total / (1 + rate / 100).