GST learning path
GST Guides: Add, Remove and Understand GST
Start with the calculator, then follow these guides in order. Each guide answers a distinct question so the cluster builds understanding without repeating the same article.
Start with the two GST formulas
Add GST: tax = base price × rate ÷ 100; inclusive total = base price + tax.
Remove GST: base price = inclusive total ÷ (1 + rate ÷ 100); tax = inclusive total − base price.
The formulas separate arithmetic from compliance. Product or service classification, place of supply, exemptions, reverse charge, input-tax credit and the legally applicable rate must be checked independently.
Use the right calculator mode
Choose Add GST when the entered amount is the taxable base. Choose Remove GST when the entered amount already includes tax. Select intra-state or inter-state only after confirming the transaction treatment.
Check the current rate separately
Check the relevant HSN or SAC classification and current official guidance before using a rate in an invoice or return. The GST Portal rate-search guidance explains how taxpayers can search rate information.