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GST Calculator

Add GST to a price, or remove GST from a price that already includes it. Choose the rate and whether the sale is within your state or to another state, and the calculator shows the taxable value, GST and the CGST/SGST or IGST split.

Rates and rules last reviewed:

What do you want to do?
Type of supply

Supplier and place of supply in the same state → CGST + SGST. Different states → IGST.

Total amount (incl. GST)

₹11,800.00

Taxable value (before GST)
₹10,000.00
Total GST @ 18%
₹1,800.00
CGST @ 9%
₹900.00
SGST/UTGST @ 9%
₹900.00
Total (incl. GST)
₹11,800.00

For guidance only

This calculator gives an estimate for general information. It is not tax or legal advice. Check the applicable rate and rules for your case on the official sources below or with a qualified professional.

How to use the GST Calculator

  1. Choose Add GST if your amount is before tax, or Remove GST if it already includes tax.
  2. Enter the amount and pick the GST rate (or enter a custom rate).
  3. Select whether the supply is within the state or between states.
  4. Copy or share the breakdown, or change any value — the result updates as you type.

Formula

Formula

Add GST: GST = Amount × Rate ÷ 100; Total = Amount + GST

Remove GST: GST = Total × Rate ÷ (100 + Rate); Amount before GST = Total − GST

Intra-state: CGST = SGST = GST ÷ 2 Inter-state: IGST = GST

How GST is calculated

GST is charged on the taxable value — the price of the goods or services before tax. The tax is a simple percentage of that value. When a price already includes GST, you cannot simply take the rate percentage of the total; you need to divide by (100 + rate) instead, because the total is 100% of the base plus the tax on top.

When is it CGST + SGST and when is it IGST?

For an intra-state supply (supplier and place of supply in the same state), GST is split equally: half as Central GST and half as State GST (or Union Territory GST). For an inter-state supply, the whole amount is Integrated GST. At 18%, that means 9% CGST + 9% SGST, or 18% IGST.

Worked examples

Adding 18% GST to ₹10,000 (sale within the state)

  1. GST = 10,000 × 18 ÷ 100 = ₹1,800
  2. CGST = SGST = 1,800 ÷ 2 = ₹900 each
  3. Total = 10,000 + 1,800

Total invoice value: ₹11,800

Removing 5% GST from ₹1,050

  1. GST = 1,050 × 5 ÷ 105 = ₹50
  2. Amount before GST = 1,050 − 50

Taxable value: ₹1,000, GST: ₹50

Important notes

  • The correct rate depends on the HSN (goods) or SAC (services) classification of what you sell. This calculator does not determine the rate for you.
  • Amounts are rounded to the nearest paisa, and CGST + SGST always add up exactly to the total GST.
  • Compensation cess, where applicable, is not included.

Frequently asked questions

How do I calculate 18% GST on an amount?

Multiply the amount by 0.18 to get the GST, then add it to the amount. For ₹2,000: GST = ₹360, total = ₹2,360.

How do I remove GST from a total?

Divide the total by (1 + rate ÷ 100). For ₹2,360 at 18%: 2,360 ÷ 1.18 = ₹2,000 before GST, so GST is ₹360. Taking 18% of ₹2,360 (₹424.80) would be wrong.

What are the current GST rates?

Following the rate rationalisation effective 22 September 2025, the main slabs are 5% and 18%, with 40% for specified goods and special rates of 0.25% and 3% for certain items. The calculator also lists the former 12% and 28% slabs for older invoices. Check the rate for your item on the official GST portal.

Is CGST + SGST more tax than IGST?

No. The total tax is the same. At 18%, an intra-state sale has 9% CGST + 9% SGST and an inter-state sale has 18% IGST.

Sources and review

Last reviewed on by the BizToolsIndia editorial team. Official references:

Spotted an error or a rate change? Tell us.

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