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GST calculator and GSTIN checker.
Add or remove GST from any amount, see the CGST, SGST or IGST split, and check whether a GSTIN is correctly formed. Everything runs in your browser; nothing you type is sent anywhere.
GSTIN checker.
Paste a GSTIN to check its structure before you put it on an invoice: state code, PAN, entity number and the check digit that catches most typing mistakes.
This checks the number's format only. To see whether a registration is active and whose it is, use the taxpayer search on the official GST portal.
About GST and GSTINs.
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How do I add GST to a price?
Multiply the price by the GST rate and add it. For ₹10,000 at 18%, GST is ₹1,800 and the total is ₹11,800. The calculator does this for any amount and rate.
How do I remove GST from a price that already includes it?
Divide the total by 1 plus the rate. For ₹11,800 including 18% GST, the price before tax is 11,800 ÷ 1.18 = ₹10,000, and the GST is ₹1,800.
When is it CGST and SGST, and when is it IGST?
A sale inside one state is intra-state: the GST is split equally into CGST and SGST. A sale from one state to another is inter-state: the whole amount is IGST.
What does the GSTIN checker test?
It checks that the 15-character number has the right structure: a valid state code, a PAN in the right format, the letter Z in the 14th place and a correct check digit. It cannot tell you whether the registration is active. For that, use the search on the official GST portal.
Which GST rate applies to my product or service?
It depends on the HSN or SAC code of what you sell. Rates were restructured from 22 September 2025, so check the current rate for your code with your accountant or on the GST portal before you invoice.