GST Calculator
Calculate the GST amount and final price for a tax-exclusive value using common Indian GST rates.
GST breakdown
How the calculation works
For a tax-exclusive amount, GST equals the base amount multiplied by the selected rate. The final price is the base amount plus GST. For example, 18% on ₹1,000 is ₹180, producing a tax-inclusive price of ₹1,180.
CGST and SGST versus IGST
An intra-state taxable supply is generally split between Central GST and State GST, so an 18% rate is commonly shown as 9% CGST plus 9% SGST. An inter-state taxable supply is generally charged as 18% IGST. The place-of-supply rules and the legal nature of the transaction determine the correct treatment.
Verify the applicable rate
The choices in this calculator are common rates, not a product-classification decision. Exempt, nil-rated and special-rate supplies also exist, and notifications can change. Confirm the HSN or SAC classification, place of supply and current notification before issuing an invoice or claiming input tax credit.
Official references
Choose whether the price includes GST
Use the add-GST option when your starting amount excludes tax. Use remove-GST when your starting amount is the final tax-inclusive price. Enter the percentage shown on the relevant invoice or verified rate notification. This calculator performs arithmetic; it does not identify the correct classification, exemption or applicable rate for a product or service.
Example: add and remove tax
For an illustrative base price of ₹1,000 and an assumed rate of 18%, GST is ₹180 and the total is ₹1,180. Working backwards from ₹1,180, divide by 1.18 to recover the ₹1,000 base. The included tax is ₹180. Multiplying the inclusive price directly by 18% would incorrectly give ₹212.40. This is why the mode you select matters.
Understand the formula
To add GST, multiply the base price by rate / 100, then add that tax to the base. To remove GST, divide the inclusive total by (1 + rate / 100), then subtract the result from the total. Keep sufficient precision during the calculation and compare the displayed rounding with your invoice. A rounded estimate can differ from an invoice calculated separately for several line items.
What this estimate leaves out
The result does not determine place of supply, input tax credit eligibility, reverse-charge treatment, compensation cess or filing obligations. It also does not split a bill containing products with different rates. Calculate each category separately using its verified base and rate, then reconcile the totals with the invoice. The example rate above is a mathematical assumption, not a claim that every purchase attracts 18%.
Read the context
Our GST explanation covers the purpose of the tax and its basic structure. Use the official-source directory when you need the notification behind an invoice. To explore other questions, open the finance calculators. Report unexpected arithmetic through contact with hypothetical inputs, not personal documents.