GST (Goods and Services Tax) is the tax charged on most goods and services sold in India. Shopkeepers, freelancers and small businesses often need two quick answers: *how much will the price be after adding GST?* and *how much GST is already included in this bill?* This calculator answers both.
How to use the GST calculator
- Choose Add GST if your price does not include GST yet, or Remove GST if the price already includes GST.
- Enter the amount.
- Enter the GST rate, or tap one of the common rates.
You get the price before GST, the total GST, the CGST and SGST split, and the final amount.
GST formulas
Add GST: GST = Amount × Rate ÷ 100
Total = Amount + GST
Remove GST: Original price = Amount × 100 ÷ (100 + Rate)
GST = Amount − Original priceExamples
Adding GST: A service costs ₹10,000 and GST is 18%.
- GST = 10,000 × 18 ÷ 100 = ₹1,800
- CGST = ₹900 and SGST = ₹900
- Total = ₹11,800
Removing GST: A bill of ₹11,800 includes 18% GST.
- Original price = 11,800 × 100 ÷ 118 = ₹10,000
- GST included = ₹1,800
A common mistake is to remove GST by taking 18% of ₹11,800, which gives ₹2,124. That is wrong, because the 18% was charged on ₹10,000, not on ₹11,800.
CGST, SGST and IGST
- For a sale within the same state, GST is split equally: half is CGST (central) and half is SGST (state). At 18%, that is 9% + 9%.
- For a sale from one state to another, the full amount is charged as IGST. At 18%, IGST is 18%.
- Union territories without a legislature use UTGST instead of SGST.
The total tax is the same in every case. Only the split changes.
Current GST rates
From 22 September 2025, GST moved to a simpler structure with two main rates, 5% and 18%, and a 40% rate for a small list of luxury and "sin" goods. Some items have special rates.
| Rate | Typical use |
|---|---|
| 0% | Many essentials, such as fresh milk and fresh vegetables |
| 3% | Gold, silver and jewellery |
| 5% | Many food items and everyday goods |
| 18% | Most services and many other goods |
| 40% | Luxury and sin goods, such as aerated sugary drinks and luxury cars |
Rates depend on the exact product or service (its HSN or SAC code) and can change after GST Council meetings. Always confirm the current rate for your item.
FAQ
How do I calculate GST from a total amount?
Choose Remove GST, enter the total and the rate. The calculator divides the total by (100 + rate) and multiplies by 100 to get the original price. The difference is the GST.
What is the difference between CGST, SGST and IGST?
CGST and SGST are charged together on sales within a state, each at half the GST rate. IGST is charged on sales between states at the full rate. The total tax is the same.
Is GST charged before or after a discount?
If the discount is given at the time of sale and shown on the invoice, GST is charged on the price after the discount.
Can I use this for a bill with items at different GST rates?
Yes. Calculate each group of items separately with its own rate, then add the results together.
Does this calculator handle cess?
No. It calculates GST only. If a compensation cess applies to your item, add it separately.