GST Calculator

Goods and Services Tax (GST) is an indirect tax system introduced in India to replace multiple indirect taxes with a single unified tax. GST created a common national market and simplified taxation across states.

Under GST, goods and services are taxed at predefined slab rates — 0%, 5%, 12%, 18% and 28%. Each product or service falls under a specific HSN code that determines the applicable GST rate.

GST is charged on the taxable value of a product or service. The final amount paid by the buyer is called the invoice value, which includes GST.

CGST, SGST and IGST Explained

For transactions within the same state, GST is split into CGST (Central GST) and SGST (State GST). For interstate transactions, IGST is charged as a single tax.

For example, if a product priced at ₹100 attracts 18% GST, the GST amount is ₹18. In an intrastate transaction, ₹9 is CGST and ₹9 is SGST. In an interstate transaction, ₹18 is charged as IGST.

Reverse GST Calculation

Sometimes prices are GST-inclusive. Reverse GST calculation helps determine the original price and GST amount included in the total. This is useful for invoice verification and cost analysis.

FastPayIn also provides a dedicated GST Reverse Calculator to make this process simple and accurate.

How to Use This GST Calculator

Enter the amount, choose the applicable GST rate, and click calculate. The calculator instantly displays the GST amount and final payable price.

This GST calculator is useful for pricing products, preparing invoices, estimating taxes, and understanding GST impact before making decisions.