Free GST calculator — add GST to a price or take it out
Use this calculator to work out GST on a price in India. You can add GST to a price that does not include it, or take GST out of a price that already does. It shows the base price, the GST amount and the final total, and splits the tax into CGST and SGST for a sale within one state, or shows it as IGST for a sale between states.
How to use the GST calculator
- Enter the amount in rupees.
- Choose Add GST if your amount is before tax, or Remove GST if your amount already includes tax.
- Pick the GST rate, or choose Custom to type a rate of your own.
- Choose whether the sale is within one state (CGST + SGST) or between states (IGST).
- Click Calculate.
The formulas
To add GST: GST amount = price × rate ÷ 100, and total = price + GST amount. To remove GST from a tax-inclusive price: base price = total × 100 ÷ (100 + rate), and GST amount = total − base price. For a sale within a state, the GST amount is shared equally between CGST (central) and SGST (state or union territory). For a sale between states, the whole amount is IGST.
Worked example
An item priced at ₹10,000 before tax, with 18% GST, carries ₹1,800 of GST, so the total is ₹11,800. In a sale within one state that is ₹900 CGST and ₹900 SGST. Going the other way, a tax-inclusive price of ₹11,800 at 18% gives a base price of ₹10,000 and ₹1,800 of GST.
About the GST rate list
India's GST was simplified on 22 September 2025, with most goods and services now at 5% or 18%, a higher 40% rate for a short list of items such as luxury and sin goods, and special low rates such as 3% on some precious metals. The 12% and 28% rates were removed for most items. Rates differ by item and can change, so always check the rate for your product or service with the official CBIC notifications or your tax adviser. If you are working with an older bill that used 12% or 28%, choose Custom and enter that rate.
Runs entirely in your browser
The calculation happens on your device. Nothing you type is sent to our servers. For quick discount and markup maths, try the percentage calculator, or see the EMI calculator for loans.
Important notice
This is a calculator for quick estimates. It does not issue a tax invoice and it does not check whether a rate applies to your product or service. It is not tax or legal advice. Confirm the correct rate and treatment with the official GST notifications or a qualified professional. SR Infobiz accepts no liability for decisions made only on the basis of this tool.
Need a custom calculator or tool built for your business? Get in touch with SR Infobiz.