CGST – + SGST – (for intra-state)
To add GST, multiply the base price by the rate: GST = price × rate ÷ 100. To remove GST from a GST-inclusive total, the base price = total × 100 ÷ (100 + rate), and the GST is the difference. For sales within the same state, GST is split equally into CGST and SGST; for inter-state sales it is charged as a single IGST.