How the GST Calculator works
Add GST: GST = Amount × rate ÷ 100. Remove GST: Base = Amount × 100 ÷ (100 + rate). Within a state the tax is split equally into CGST and SGST; between states it is charged as IGST.
Since GST 2.0 (September 2025) most goods fall under 5% or 18%, with 40% for select luxury and sin goods. Older rates are kept for reference.