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GST Calculator

Add GST to a price or remove GST from an inclusive amount, and see the CGST/SGST or IGST split instantly. Free and 100% private.

3%
5%
12%
18%
28%
Custom
Base amount
GST (18%)
Total amount

How to calculate GST

  1. Enter your amount.
  2. Choose the GST rate — 3%, 5%, 12%, 18%, 28% or a custom rate.
  3. Pick Add GST for a base price, or Remove GST for a GST-inclusive total.
  4. See the GST amount, the CGST/SGST or IGST split, and the final total.

Add vs remove GST

Add GST takes your base price and adds tax on top — useful when quoting or making an invoice. Remove GST works backwards from a GST-inclusive amount to reveal the original price and the tax inside it — useful for reconciling receipts.

CGST, SGST and IGST

For a sale within the same state, GST splits equally into CGST and SGST. For a sale to another state, the full amount is charged as IGST. This tool shows the right breakdown for both.

Frequently asked questions

Is this an official GST tool?

No — it's a free calculator for quick estimates. Always confirm the correct GST rate and rules for your goods or services with a professional.

Are my numbers sent anywhere?

No. All calculations run in your browser; nothing is uploaded or stored on any server.