GST calculator
Add GST to a price, or take it out of one, and see the CGST and SGST or IGST split. It uses the same arithmetic as an invoice made in PlusGST, and nothing you type leaves your browser.
The GST, worked out
Price including GST
₹11,800.00
- Price before GST
- ₹10,000.00
- CGST at 9%
- ₹900.00
- SGST at 9%
- ₹900.00
- Total GST
- ₹1,800.00
GST is 18% of the price, split equally into CGST and SGST.
How GST is worked out
GST is a percentage of the taxable value: the price of what you sell, after any discount you give on the invoice. At 18%, a price of ₹10,000.00 carries ₹1,800.00 of GST, and the customer pays ₹11,800.00.
Who gets the tax depends on where your customer is. A sale within your state is taxed as CGST and SGST, in equal halves, so 18% becomes 9% CGST and 9% SGST. A sale to another state is taxed as IGST, all at the full rate. The total is the same either way. PlusGST decides this from the GST state codes of your business and your customer.
| Rate | CGST | SGST | Or IGST | Total |
|---|---|---|---|---|
| 5% | ₹250.00 | ₹250.00 | ₹500.00 | ₹10,500.00 |
| 12% | ₹600.00 | ₹600.00 | ₹1,200.00 | ₹11,200.00 |
| 18% | ₹900.00 | ₹900.00 | ₹1,800.00 | ₹11,800.00 |
| 28% | ₹1,400.00 | ₹1,400.00 | ₹2,800.00 | ₹12,800.00 |
| 40% | ₹2,000.00 | ₹2,000.00 | ₹4,000.00 | ₹14,000.00 |
Taking GST out of a price
When a price already includes GST, divide it by 100 plus the rate, and multiply by 100. At 18%, ₹11,800.00 × 100 ÷ 118 = ₹10,000.00 before GST, and the GST in it is ₹1,800.00. Choose “A price with GST in it” in the calculator to do this.
Tax is rounded to the paisa, and CGST and SGST are rounded separately, so at some rates no price in whole paise adds up exactly to the amount you started from. The calculator then shows the nearest and tells you the difference.
Which rate applies
The rate depends on what you sell: the HSN code of the goods or the SAC code of the service. Since 22 September 2025 most goods and services are taxed at 5% or 18%, and 40% applies to a short list of goods. 12% and 28% still appear on a few items and on bills from before that date. Confirm the rate for your items with your CA or on the GST portal; this page is general information, not tax advice.
On an invoice
In PlusGST the same calculation runs on every line of an invoice, after any invoice discount is spread across the items, with shipping taxed at 18% when you choose. See the invoicing page, or read what a GST invoice has to carry.
Questions, answered plainly.
More on the FAQ page.
Is the GST calculator free? Does it keep what I type?
It is free and needs no account. Nothing you type leaves your browser.
Why is CGST half of the rate?
For a sale within your state, GST is charged as CGST and SGST in equal halves, so 18% is 9% CGST and 9% SGST. For a sale to another state it is all IGST at the full rate. The total tax is the same either way.
How do I take GST out of a price that includes it?
Multiply the price by 100 and divide by 100 plus the rate. At 18%, ₹11,800 × 100 ÷ 118 gives ₹10,000 before GST, so the GST in it is ₹1,800.
Which GST rate applies to what I sell?
That depends on the HSN code of the goods or the SAC code of the service. Since 22 September 2025 most goods and services are taxed at 5% or 18%, with 40% on a short list of goods. Confirm the rate for your items with your CA or on the GST portal.
Why is the answer sometimes a paisa off?
Tax is rounded to the paisa, and CGST and SGST are each rounded. At some rates no price in whole paise adds up exactly to the amount you typed, so the calculator shows the nearest and says so.
Is it the same calculation PlusGST uses on invoices?
Yes. The calculator uses the same code as the invoice builder, so its figures match an invoice made in PlusGST.
From a number to an invoice.
The calculator answers one sum. PlusGST does it on every line, and keeps the result.
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