Need to calculate GST in India? Our free GST Calculator makes it easy to add GST to a price or remove GST from a GST-inclusive amount. Enter the amount, choose the GST rate, and select whether you want to add or remove GST.
The calculator shows the GST amount, CGST and SGST for an intra-state transaction, IGST for an inter-state transaction, and the final amount. It supports common GST rates used in India and is useful for invoices, billing, shopping, business pricing, and quick GST calculations.
What Is a GST Calculator?
A GST Calculator is a simple tool that helps you calculate Goods and Services Tax on a price or amount in India.
You can use it to add GST to an amount that does not include tax or remove GST from an amount that already includes GST. The calculator also shows the GST amount and breaks it down into CGST and SGST for intra-state transactions or IGST for inter-state transactions.
GST rates depend on the goods or services being supplied, so you should select the applicable rate for your transaction. India’s GST rate structure was rationalised in 2025, with a standard 18% rate, a 5% merit rate, and a special 40% rate for selected goods and services.
How to Use the GST Calculator
Using the calculator is easy:
- Choose Add GST to Amount if your entered amount does not include GST.
- Choose Remove GST from Amount if your entered amount already includes GST.
- Enter the amount.
- Select the applicable GST rate.
- Choose Intra-State or Inter-State.
- Click Calculate.
The calculator will show the GST amount and the resulting price.
Add GST to a Price
When you have a price before GST, the calculator adds the selected GST rate to the amount.
For example, if a product costs ₹1,000 before GST and the applicable GST rate is 18%:
- Price before GST = ₹1,000
- GST = ₹180
- Final price = ₹1,180
The calculation is:
GST = ₹1,000 × 18% = ₹180
Final Amount = ₹1,000 + ₹180 = ₹1,180
Remove GST From an Inclusive Price
Sometimes the price you see already includes GST. In that situation, you cannot simply subtract the GST percentage from the total.
For example, if the GST-inclusive price is ₹1,180 and the GST rate is 18%, the pre-GST amount is calculated as:
₹1,180 ÷ 1.18 = ₹1,000
The GST portion is:
₹1,180 − ₹1,000 = ₹180
This is why the calculator has a separate Remove GST from Amount option.
What Is CGST?
CGST stands for Central Goods and Services Tax.
For an intra-state supply where CGST and SGST apply, the GST amount is generally divided equally between CGST and SGST when the applicable GST rate is split evenly.
For example, with an 18% GST rate:
- CGST = 9%
- SGST = 9%
The GST Council’s rate structure and notifications determine the applicable tax rates.
What Is SGST?
SGST stands for State Goods and Services Tax.
For an applicable intra-state transaction, GST is collected through CGST and SGST components.
For example, an 18% GST rate can be represented as:
- CGST = 9%
- SGST = 9%
The exact tax treatment depends on the nature and location of the supply.
What Is IGST?
IGST stands for Integrated Goods and Services Tax.
For applicable inter-state supplies, the GST is charged as IGST rather than being split into CGST and SGST on the invoice.
The calculator therefore lets you choose between:
- Intra-State — CGST + SGST
- Inter-State — IGST
Intra-State vs. Inter-State GST
The type of GST depends partly on whether the supply is within a state or between states.
For an applicable intra-state supply, the GST amount is generally represented by CGST and SGST.
For an applicable inter-state supply, IGST is generally used.
The actual tax treatment can depend on the place-of-supply rules and the specific transaction, so businesses should check the applicable GST provisions for their situation.
GST Calculation Formula
When adding GST to a price:
GST Amount = Original Amount × GST Rate ÷ 100
Then:
Total Amount = Original Amount + GST Amount
When removing GST from a GST-inclusive amount:
Original Amount = GST-Inclusive Amount ÷ (1 + GST Rate ÷ 100)
Then:
GST Amount = GST-Inclusive Amount − Original Amount
GST Calculation Example
Suppose the price of a product before GST is ₹5,000 and the applicable GST rate is 18%.
GST:
₹5,000 × 18% = ₹900
Final price:
₹5,000 + ₹900 = ₹5,900
For an intra-state transaction, the ₹900 GST can be shown as:
- CGST = ₹450
- SGST = ₹450
For an inter-state transaction, the GST amount would be shown as:
- IGST = ₹900
GST Rate in India
GST rates depend on the particular goods or services and their applicable classification.
Following the 56th GST Council meeting in September 2025, India moved toward a simplified structure with a 5% merit rate and an 18% standard rate, along with a special 40% rate for selected goods and services. Most of these revised rates became effective from 22 September 2025.
Because GST rates can change and different products or services can have different rates, always check the applicable rate before preparing an invoice or calculating tax.
Does GST Apply to Every Product?
No. GST treatment depends on the goods or services involved.
Some supplies can be exempt, while others can have different GST rates or special provisions. The applicable rate should therefore be checked for the specific product or service rather than assumed.
The GST Council publishes rate notifications and rate information for goods and services.
GST on Goods and Services
GST applies to supplies of goods and services under India’s GST framework, but the applicable rate and tax treatment can vary.
For businesses, the correct classification and applicable rate are important when creating invoices and calculating tax.
GST Inclusive vs. GST Exclusive Price
A GST-exclusive price is the amount before GST is added.
A GST-inclusive price already contains GST.
For example:
GST-exclusive: ₹1,000
GST at 18%: ₹180
GST-inclusive: ₹1,180
Knowing whether a price is inclusive or exclusive of GST is important when comparing prices or preparing invoices.
GST Calculator for Businesses
Businesses can use a GST calculator for quick calculations when preparing quotations, checking prices, or reviewing invoices.
However, a calculator should not replace proper GST accounting or professional tax advice. Businesses also need to consider applicable GST rules, input tax credit, place-of-supply provisions, invoice requirements, exemptions, and other compliance requirements.
GST Calculator for Shoppers
Consumers can also use the calculator to understand how much GST is included in a price.
For example, if a listed price is exclusive of GST, you can add the applicable GST rate to estimate the final amount.
If the displayed price already includes GST, you can use the Remove GST from Amount option to estimate the price before GST.
Frequently Asked Questions
What is GST?
GST stands for Goods and Services Tax. It is India’s indirect tax system covering supplies of goods and services under the GST framework.
How do I calculate GST?
To add GST, multiply the amount by the GST rate divided by 100.
For example, at 18% GST on ₹1,000:
₹1,000 × 18% = ₹180 GST
The final amount is ₹1,180.
How do I remove GST from an inclusive price?
Divide the GST-inclusive amount by 1 + GST rate ÷ 100.
For example, at 18% GST:
₹1,180 ÷ 1.18 = ₹1,000
What is the difference between CGST and SGST?
CGST is the Central GST component and SGST is the State GST component. For applicable intra-state supplies, both can apply to the same transaction.
What is IGST?
IGST stands for Integrated Goods and Services Tax and is used for applicable inter-state supplies.
Is GST always 18% in India?
No. The applicable GST rate depends on the goods or services and the relevant classification. The GST rate structure has also changed over time. The 2025 reforms introduced a 5% merit rate, 18% standard rate, and special 40% rate for selected goods and services.
Does this calculator include GST rates for every product?
No. The calculator provides selectable rates for calculation purposes. It does not determine the legally applicable GST rate for a particular product or service.
Can I use this calculator for invoices?
Yes, it can be used for quick calculations and checking amounts. However, businesses should verify the applicable GST rate, classification, place of supply, and other invoice requirements before issuing an actual tax invoice.
Can I calculate CGST and SGST?
Yes. Select Intra-State (CGST + SGST) and the calculator will split the GST amount equally between CGST and SGST.
Can I calculate IGST?
Yes. Select Inter-State (IGST) and the calculator will show the full GST amount as IGST.
Disclaimer: This GST Calculator is provided for general informational and calculation purposes only. GST rates, exemptions, classifications, and tax rules can change. Always verify the applicable GST rate and tax treatment for the specific goods or services before preparing an invoice or making a tax decision.