GST Calculator: Add or Remove GST With CGST and SGST
Our GST calculator adds GST to a price or removes it from a total that already includes tax. It also splits the tax into CGST and SGST for sales within one Indian state. Pick a common rate from the list or type your own.
What GST Is
GST, or goods and services tax, is a tax added to most goods and services at each stage of sale. India, Australia, New Zealand, Singapore and Canada all use it, each at its own rate. Businesses collect it from buyers and pass it on to the government.
How to Use the GST Calculator
- Choose Add GST if your price does not include tax yet.
- Choose Remove GST if the amount you have already includes tax.
- Pick a rate from the list or type any rate in the box.
- Read the GST amount, both prices and the CGST and SGST split.
Every result updates the moment you change a number. The list covers the current Indian slabs, the older ones and the standard rates of four other countries. Typing your own rate clears the list choice so you always see which rate is in use.
How to Calculate GST
Adding GST to a Price
Multiply the price by the rate and divide by 100 to get the tax. For a price of 1,000 at 18 percent, the GST is 180 and the final price is 1,180. Add the two together and you have the amount the buyer pays.
Removing GST From a Total
To find the price before tax, divide the total by one plus the rate as a decimal. For 1,180 at 18 percent, 1,180 ÷ 1.18 gives 1,000, so the GST inside the total is 180. A reverse GST calculator does this in one step and avoids a common slip.
That slip is taking 18 percent of the total itself. On 1,180 it gives 212.40, which overstates the tax by 32.40. The correct GST formula always divides by 1.18 first when the price already includes tax.
The GST Formula in Short
- Adding: GST = price × rate ÷ 100, and total = price + GST.
- Removing: price = total ÷ (1 + rate ÷ 100), and GST = total − price.
CGST and SGST Split
Inside one Indian state, GST is shared equally between the central and state governments. The central part is CGST and the state part is SGST, so an 18 percent rate becomes 9 percent plus 9 percent. On a 1,000 sale that means 90 as CGST and 90 as SGST.
When goods move from one state to another, the whole tax is charged as IGST instead. The same 1,000 sale would show 180 as IGST with no CGST and SGST lines. Union territories without their own legislature use UTGST in place of SGST.
GST Rates in India
From 22 September 2025, most goods and services fall under two main slabs of 5 and 18 percent. A 40 percent rate covers a short list of luxury and sin goods, while many essentials stay at zero. Always check the rate for your exact product before you bill a customer.
The older 12 and 28 percent slabs still appear on invoices dated before the change. The tool keeps them in a separate group so you can check or correct past bills. The GST Council announces every change, so confirm the latest notice for anything unusual.
GST in Other Countries
The idea is the same everywhere, but the rate changes by country. Canada adds a 5 percent federal GST, and some provinces combine it with their own tax into a single HST. Use the list or type the rate that applies to you.
| Country | Standard GST rate |
| India | 5% or 18% (40% for luxury and sin goods) |
| Australia | 10% |
| New Zealand | 15% |
| Singapore | 9% |
| Canada | 5% federal GST |
GST Inclusive Price vs Exclusive Price
An exclusive price is the amount before tax, while a GST inclusive price already has the tax built in. Shops in Australia, New Zealand and Singapore must usually show the tax inclusive price on the shelf. Businesses often quote exclusive prices to each other, so check which one an invoice shows first.
A Worked Invoice Example
A supplier in Mumbai sells goods worth 25,000 to a buyer in the same state at 18 percent. The GST comes to 4,500, the CGST and SGST shares are 2,250 each and the invoice total is 29,500. If the buyer were in another state, the full 4,500 would appear as IGST.
Why Use Our GST Calculator
This page handles adding and removing tax, shows the state split and keeps both old and new Indian slabs in one list. It runs fully in your browser, so no figures leave your device. Enter an amount and calculate your GST now.
Frequently asked questions
Is this GST calculator free?
Yes, it is free with no sign up and no limit.
How to calculate GST on a price that already includes tax?
Divide the total by 1 plus the rate as a decimal, then subtract that from the total.
When should I use a reverse GST calculator?
Use it whenever the amount you have already includes GST.
Why are CGST and SGST always equal?
The tax is shared half and half between the central and state governments.
What are the main GST rates in India now?
Since 22 September 2025 the main slabs are 5 and 18 percent, with 40 percent for luxury and sin goods.
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