GST Calculator
Work out GST free in your browser: enter an amount, pick a 0, 5, 12, 18 or 28 percent slab, and choose whether tax is already included.
- Add
- Adjust
- Make
- Keep
How to use this tool
- Enter the amount and pick a GST slab: 0, 5, 18 or 40 percent, or the older 12 or 28 percent for invoices dated before 22 September 2025.
- Choose whether the figure already includes tax or whether GST should be added on top.
- Read the live taxable amount, GST and total, then download a one-page PDF of the working.
About this tool
Work out GST free in your browser: enter an amount, pick a 0, 5, 12, 18 or 28 percent slab, and choose whether tax is already included. Nothing is uploaded; the split is calculated on your device and you can download a one-page PDF of the working without creating an account.
Privacy & limitations
This is arithmetic on the public GST slabs only. It does not look up HSN codes, does not split CGST/SGST versus IGST from state codes, and does not file anything with the GST portal.
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Frequently asked questions
How do I calculate GST on an amount?
Multiply the amount by the GST rate and divide by 100, then add it to the amount. For 10,000 at 18% the GST is 1,800 and the total is 11,800. Choose the rate, enter the amount, and keep the add GST on top option selected.
How do I remove GST from a GST-inclusive price?
Choose the option that says the amount includes tax. The taxable value is the amount × 100 / (100 + rate), and GST is the difference. A price of 1,180 including 18% GST has a taxable value of 1,000 and GST of 180.
Which GST rates does it support?
It offers 0%, 5%, 18% and 40%, the slabs in force from 22 September 2025, plus the older 12% and 28% slabs so you can check earlier invoices. Confirm the rate for your product or service on the official GST rate schedule, as the tool does not know it.
Does it split CGST and SGST or file my return?
No. It calculates the total GST only. It does not look up HSN codes, decide between CGST plus SGST and IGST, or file anything with the GST portal. To produce a complete invoice, use the GST Invoice Generator on this site.