GST Calculator India to Add or Remove GST

Guide

Formulas used

Add GST: GST = Amount × Rate ÷ 100, Total = Amount + GST. Remove GST: Taxable value = Amount × 100 ÷ (100 + Rate), GST = Amount − Taxable value. For an intra-state sale the GST is split equally into CGST and SGST (for example 18% = 9% + 9%); for an inter-state sale the whole amount is IGST. Values are rounded to the nearest paisa.

Which rate applies?

India’s GST rates depend on the HSN or SAC code of the goods or service. After the 2025 rate rationalisation most goods fall under 5% or 18%, with a higher rate for some luxury and sin goods, and some essentials are exempt. Rates change by government notification, so confirm the current rate for your item on the official GST portal or with your accountant before you raise an invoice.

Second-hand goods and GST

Private individuals selling their own used phone, bike or furniture on FastBuySale generally do not charge GST, because they are not running a registered business. Dealers who trade in used goods may need to charge GST, sometimes only on their margin. This calculator is for estimates and learning; it is not tax advice.

Worked examples

Adding GST: a service worth ₹1,000 at 18% → GST ₹180 (CGST ₹90 + SGST ₹90), invoice total ₹1,180. Removing GST: a price of ₹1,180 inclusive of 18% → taxable value ₹1,000 and GST ₹180. A ₹2,500 item at 5% → GST ₹125, total ₹2,625. An inclusive bill of ₹47,200 at 18% → taxable value ₹40,000 and GST ₹7,200; if it was sold to another state, the whole ₹7,200 is IGST.