Add GST to a price, or work backwards from a GST-inclusive amount to the original price. The result also shows the CGST and SGST split for sales within a state, or the IGST amount for sales between states.
How GST is calculated
- To add GST: GST amount = price x rate / 100, and total = price + GST amount
- To remove GST: price before GST = total x 100 / (100 + rate), and GST amount = total – price before GST
- Within one state the GST is split equally into CGST and SGST. Between states the whole amount is charged as IGST.
Worked example
An invoice for Rs 10,000 with 18% GST adds Rs 1,800, so the customer pays Rs 11,800. For a sale within one state, that Rs 1,800 is shown as Rs 900 CGST and Rs 900 SGST. Working backwards, a GST-inclusive price of Rs 11,800 at 18% gives 11,800 x 100 / 118 = Rs 10,000 before tax.
A note on rates
GST rates and the goods or services that fall under each rate are decided by the GST Council and have changed several times, most recently with a simplification of the main slabs. The 12% and 28% options are kept in the list so you can check older invoices. Always confirm the rate that applies to your product or service on the official GST portal or with your tax professional before you issue an invoice.
Frequently asked questions
Is the amount I enter with or without GST?
You choose. Use the first option when your amount excludes GST, and the second when it already includes GST.
Why are CGST and SGST equal?
For sales within the same state, the tax is shared equally between the central and the state government, so each is half of the total GST rate.
Can I claim input tax credit with this tool?
No. This tool only splits a single amount. Input tax credit depends on your registration, your purchases and the rules in force, so speak to your accountant.
This calculator is provided for general information and planning only. It is not accounting, tax, legal or investment advice, and the results depend entirely on the numbers you enter. Please confirm important figures with a qualified professional.