How to calculate GST
- Choose 'Add GST' or 'Remove GST' and type the amount.
- Pick the GST rate, or type your own.
- Read the CGST, SGST or IGST and the total.
About this tool
Use this to find the GST on a price, or to find the price before GST when you only know the total. Pick a rate or type your own, then choose same-state sales to see CGST and SGST, or other-state sales to see IGST. Since 22 September 2025 most items are taxed at 5% or 18%, but the rate box stays editable because it depends on the item.
Common questions
How do I take GST out of a price that already includes it?
Divide the total by 1 plus the rate. At 18%, divide by 1.18. For 1,180 the price before GST is 1,000 and the GST is 180.
Which GST rate should I use?
It depends on the item. Check your invoice or the GST rate finder on the government GST portal. The shortcuts on this page are common rates and you can type any other.
When is it CGST and SGST, and when IGST?
For a sale within one state, GST is split equally into CGST and SGST. For a sale to another state, the whole amount is IGST.
Is it free to use?
Yes. There's no sign-up, and you can use it as often as you like.
Is my text uploaded anywhere?
No. This tool runs inside your browser, so what you enter stays on your device.
Do I need to install anything?
No. It works in your browser on a computer or a phone.