GST Calculator

What Is a GST Calculator?

A GST Calculator is a free online tool that helps you calculate Goods and Services Tax (GST) on products and services. It determines the GST amount, original price, and total price based on the tax rate you enter.

Our GST Calculator supports both GST-inclusive and GST-exclusive calculations. It also helps you calculate CGST, SGST, and IGST amounts for applicable transactions in India.

GST is a consumption tax used in India and several other countries. If you need to calculate a tax applied to purchases in another jurisdiction, you can also use our Sales Tax Calculator.

How to Use the GST Calculator

Follow these steps to calculate GST online:

1. Enter the Amount: Enter the original price or GST-inclusive amount, depending on your calculation.

2. Select GST Type: Choose whether you want to add GST to a base price or remove GST from a tax-inclusive price.

3. Enter GST Rate: Select an available GST rate or enter a custom percentage.

4. Choose Tax Breakdown: Select the applicable CGST and SGST or IGST calculation option, if available.

5. Click Calculate: View the GST amount, taxable value, and final price.

The calculator applies the selected GST rate and displays the corresponding tax breakdown.

Note: The calculator performs GST arithmetic using your selected rate. It does not automatically determine which GST rate or tax category legally applies to a particular product or service.

GST Calculation Formula

GST can be calculated in two ways: by adding tax to the original price or by extracting tax from a price that already includes GST.

1. GST Exclusive Formula (Add GST)

Use this formula when the original price does not include GST.

$\text{GST Amount}=\frac{\text{Original Price}\times\text{GST Rate}}{100}$

$\text{Final Price}=\text{Original Price}+\text{GST Amount}$

For example, if a product costs ₹1,000 before GST and the applicable GST rate is 18%:

$\text{GST Amount}=\frac{1000\times18}{100}=\text{₹}180$

$\text{Final Price}=1000+180=\text{₹}1180$

The final price, including GST, is ₹1,180.

If you want to calculate tax percentages manually or compare different percentage values, try our Percentage Calculator.

2. GST Inclusive Formula (Remove GST)

Use this formula when the amount already includes GST and you want to calculate the original price.

$\text{Original Price}=\frac{\text{GST Inclusive Price}\times100}{100+\text{GST Rate}}$

$\text{GST Amount}=\text{Inclusive Price}-\text{Original Price}$

For example, suppose a product costs ₹1,180, including 18% GST.

$\text{Original Price}=\frac{1180\times100}{118}=\text{₹}1000$

$\text{GST Amount}=1180-1000=\text{₹}180$

The original price is ₹1,000, and the included GST amount is ₹180.

GST Calculation Examples

Here are examples of how different GST rates affect a product's final price.

Suppose the original product price is ₹2,000.

These examples demonstrate the mathematical effect of different rates. They do not mean that every product or service can be taxed at each rate.

GST Inclusive vs. GST Exclusive

The difference depends on whether GST is already included in the entered price.

For example, ₹1,000 plus 18% GST becomes ₹1,180. Conversely, removing the included 18% GST from ₹1,180 gives an original value of ₹1,000.

GST and Value Added Tax (VAT) use similar percentage-based calculations. For VAT-specific calculations, you can use our VAT Calculator.

CGST vs. SGST vs. IGST

In India, GST is generally collected through different tax components depending on the nature and place of supply.

How to Calculate CGST and SGST

For a typical intra-state transaction, the total GST rate is divided equally between CGST and SGST.

$\text{CGST}=\frac{\text{Total GST}}{2}$

$\text{SGST}=\frac{\text{Total GST}}{2}$

Example:

Suppose the taxable value is ₹5,000 and the applicable GST rate is 18%.

For eligible supplies within a Union Territory, UTGST may apply instead of SGST.

How to Calculate IGST

For an applicable inter-state transaction, IGST is generally calculated using the full GST rate.

$\text{IGST}=\frac{\text{Taxable Value}\times\text{GST Rate}}{100}$

For example, if the taxable value is ₹5,000 and the applicable IGST rate is 18%:

$\text{IGST}=\frac{5000\times18}{100}=\text{₹}900$

The final amount is ₹5,900.

The actual tax treatment depends on the place-of-supply rules and the nature of the transaction.

GST Rates in India (2026)

India's GST framework was restructured in September 2025. The revised framework generally focuses on two main GST rates of 5% and 18%, along with a special 40% rate for specified goods and services.

Some supplies are exempt, zero-rated, or subject to special rates, exceptions, and transitional provisions. Exempt and zero-rated supplies have different legal meanings.

Important: The applicable GST rate depends on the classification of the product or service, transaction date, and relevant government notifications.

You can enter a custom rate in the calculator when working with historical invoices or supplies subject to a different applicable rate.

For the latest GST information, refer to the GST Council and official tax notifications.

Common GST Calculation Mistakes

Avoid these common errors when calculating GST:

• Using the Wrong GST Rate: Verify the rate applicable to the product or service instead of assuming all items have the same rate.

• Confusing Inclusive and Exclusive Prices: Check whether GST is already included before adding tax.

• Applying GST Twice: Do not add GST again to a price that already includes it.

• Using the Wrong Tax Type: Check whether CGST and SGST/UTGST or IGST apply to the transaction.

• Ignoring Discounts: Determine the correct taxable value and treatment of discounts before calculating GST. If you need to calculate a discounted selling price, use our Discount Calculator before applying the appropriate GST treatment.

• Using Outdated Rates: Verify the transaction date and applicable GST notifications, especially for historical invoices.

The calculator can help you check the arithmetic, but accurate tax calculations still depend on choosing the correct rate and taxable value.

Disclaimer: This GST Calculator provides mathematical estimates for informational purposes. It does not determine GST classification, eligibility for exemptions, input tax credits, or tax compliance obligations. Verify applicable rates and rules using official government notifications or consult a qualified tax professional.