GST Calculator
GST Calculator adds or removes Goods and Services Tax, and shows the CGST and SGST split, free and in your browser. You enter an amount and a GST rate, and choose whether to add GST to it or remove GST from it.
Last updated: 30 October 2026 · Free · No signup
GST is a tax added to the price of most goods and services in India. When GST is added, the total price is the original price plus the tax. When GST is removed, the original price is worked back from a price that already includes tax, which is not the same as simply subtracting the percentage. For sales within a state, the tax is normally split equally between CGST and SGST, and this tool shows that split.
Be clear about whether your starting price already includes GST or not, because that decides whether you should add or remove it. Adding GST to a price that already includes it, or removing GST from a price that does not include it, will both give a wrong result, even though the arithmetic itself is simple.
Privacy: this tool runs entirely in your browser — no upload, no signup, and your files never leave your device.
Add GST to a price, or separate the GST out of a GST-inclusive price — with the CGST and SGST shares shown. The calculation to do before making a bill.
How to use GST Calculator
- Enter the amount.
- Choose the GST rate, or enter a custom rate.
- Choose add GST or remove GST.
- Read the GST amount, the total, and the CGST/SGST split.
Key facts
| Modes | Add GST to a price, or remove GST from a price |
|---|---|
| Split shown | CGST and SGST, split equally for within-state sales |
| Rates | Common GST rates, plus a custom rate option |
Frequently asked questions
How do I add 18% GST to a price?
Multiply the price by 18 and divide by 100 to get the GST amount, then add it to the price. For a price of 1,000, the GST is 180, so the total with GST is 1,180. This tool does that calculation and shows the CGST and SGST split as well.
How do I remove GST from a price that already includes it?
Divide the total price by 1 plus the GST rate as a decimal. For 18% GST, divide by 1.18. Simply subtracting 18% from the total gives a wrong answer, because the percentage was applied to the original price, not to the total.
What are CGST and SGST?
CGST is the central share of GST and SGST is the state share. For a sale within the same state, the total GST is normally split equally between them, so 18% GST becomes 9% CGST plus 9% SGST.
Are my amounts uploaded or saved?
No. Calculation happens in your browser only. Nothing is sent to a server and nothing is saved after you close the page.