Add GST or extract it from an inclusive price
For a tax-exclusive amount, GST equals the taxable value multiplied by the entered rate, and the invoice total is taxable value plus GST. For a tax-inclusive amount, the taxable value is the total divided by one plus the rate; subtracting that value from the total extracts the embedded GST. Simply multiplying an inclusive total by the rate would overstate the tax.
CGST, SGST and IGST split
For the simplified Indian intra-state view, the calculated GST is divided equally between CGST and SGST or UTGST. For the inter-state view, the same total is shown as IGST. Place-of-supply, registration, reverse-charge, composition-scheme, import, export, and special transaction rules can change the legal treatment.
Rate shortcuts are not product classification
The preset rates are calculation shortcuts, not a conclusion about a product or service. The applicable rate depends on current law, HSN or SAC classification, exemptions, conditions, transaction date, and notifications. Search the official GST Portal HSN/SAC service and review the latest notifications on the CBIC Tax Information Portal before issuing or checking an invoice. Rates and classifications can change, so the custom-rate option remains available.
Rounding and invoice systems can differ
This calculator shows currency values to two decimals after performing the calculation at full JavaScript precision. Accounting software may round each line, tax component, or invoice total differently. Discounts, freight, cess, multiple line items, credit notes, input tax credit, and taxable-value rules are outside this single-amount estimate.
This tool only applies the rate and price type you select. It does not identify taxability, classification, place of supply, filing treatment, or the legally correct rate and is not tax, accounting, or legal advice. Verify current official rules and obtain qualified advice when needed.