GST is calculated on the taxable value of supplies considering the GST rate applicable on the product or services. Let’s say if the taxable value is 10,000 and the GST rate is 18%, the total GST calculated is 1800. This is split into CGST (900) and SGST (900) if it is intrastate supplies. In case of inter-state, the entire GST will be calculated as IGST