GST Calculator

Add GST to a price, or remove GST from a price that already includes it. Split the tax into CGST and SGST, or show IGST.

Enter the values and press Calculate.

Your result will show here.

About this calculator

Goods and Services Tax is charged on most supplies in India. You either add it to a price that is still exclusive, or you peel it out of a price that already includes it. Both are common on bills, and they are not the same sum.

Adding 18% to ₹100 gives ₹18 of tax and a total of ₹118. Removing 18% from ₹118 gives a base of ₹100, not ₹18 less than ₹118 in a careless subtraction. The inclusive formula divides by 1.18.

CGST and SGST apply when the supplier and the place of supply are in the same state. IGST applies when they are in different states, or in the cases the GST law treats as inter-state. The calculator splits the tax. It does not decide which kind of supply you made.

Always check the rate for the specific HSN or SAC before you invoice. Rates move by notification. The 12% and 28% slabs were largely removed in the September 2025 rationalisation, but a notification for one item beats a general list.

GST formula

GST = base × rate ÷ 100
Total = base + GST

If the amount already includes GST:
Base = amount ÷ (1 + rate ÷ 100)
GST = amount − base

On a supply inside one state, CGST and SGST are each half of the GST. On a supply between states, the whole GST is IGST.

Example: ₹10,000 before 18% GST

An amount of ₹10,000 before tax, at 18%, supplied inside one state.

GST is ₹1,800.00. The total is ₹11,800.00. CGST and SGST are each half of the GST.

If a customer is in another state, the same GST is shown as IGST instead of CGST and SGST. The total does not change.

₹10,000 plus 18% GST

Same-state split.

₹11,800.00

How to use

Enter the amount.
Choose the GST rate, or choose Other rate and type one.
Say whether the amount is before GST or already includes it.
Choose same-state or inter-state supply.
Press Calculate and read the base, the tax, and the total.

Important notes

From 22 September 2025 the main slabs most people meet are nil, 5%, and 18%, with 40% on selected luxury and sin goods. Special rates such as 3% and 0.25% still exist.
The rate depends on the exact goods or service. This list is a shortcut, not a classification ruling.
A tax invoice should show the rate and the split your supply actually needs.
This tool does not prepare a GST return.

FAQ

How do I remove GST from a price?

Choose “Including GST”. The calculator divides the amount by (1 + rate). For 18%, it divides by 1.18.

Why are CGST and SGST equal?

On a same-state supply the GST is split into two equal parts, central and state. IGST is used instead when the supply is between states.

Is 18% the rate for everything?

No. 18% is the standard rate for many goods and services after the 2025 rationalisation. Food, some essentials, gold, and specified luxury goods use other rates.

Does this file my GST return?

No. It only splits one amount. Returns, input tax credit, and e-invoicing are outside this page.

Disclaimer

Results are estimates for general information. Verify important decisions with an appropriate professional or official source. Confirm the GST rate and place of supply before you raise an invoice.

Last updated 5 October 2026.

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