GST (Goods and Services Tax) was introduced in India on 1st July 2017, replacing a complex system of multiple indirect taxes. Whether you are a business owner, accountant, freelancer or consumer, understanding how to calculate GST is essential in India today.
In this complete guide, we will explain all GST slabs, show you the exact formulas to add or remove GST from any price, and introduce you to our free online GST calculator that does all the math instantly.
What are the GST Slabs in India?
India has five GST tax slabs. Every product and service falls under one of these categories:
| GST Rate | Category | Common Examples |
|---|---|---|
| 0% | Exempt goods | Fresh milk, eggs, vegetables, fruits, bread, salt, books |
| 5% | Essential items | Sugar, tea, coffee, edible oil, packaged food, medicines |
| 12% | Standard goods | Butter, cheese, mobile phones, computers, processed food |
| 18% | Most goods/services | Soap, shampoo, toothpaste, banking services, restaurants |
| 28% | Luxury items | Cars, AC, cement, tobacco, paint, luxury hotels |
How to Calculate GST — The Formula
Adding GST to a Price (Exclusive GST)
When a price is mentioned without GST and you need to find the final price including GST:
Final Price = Original Price + GST Amount
Example: ₹1000 + 18% GST
GST = ₹1000 × 0.18 = ₹180
Final Price = ₹1000 + ₹180 = ₹1,180
Removing GST from a Price (Inclusive GST)
When a price already includes GST and you need to find the base price:
GST Amount = Final Price - Original Price
Example: ₹1180 inclusive of 18% GST
Original = ₹1180 / 1.18 = ₹1,000
GST Amount = ₹1180 - ₹1000 = ₹180
What is CGST and SGST?
When GST is collected on goods and services sold within the same state, it is split equally into two parts — CGST (Central GST) and SGST (State GST). Each part goes to the central and state government respectively.
For example, on an 18% GST product: CGST = 9% and SGST = 9%. For interstate sales, IGST (Integrated GST) at the full rate applies instead.