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Calculates

GST Calculator

Add or remove GST and instantly calculate the tax amount and final price.

Calculated & verified for mathematical accuracy·Reviewed by the Calculates Editorial Team

Amount & tax

Calculation mode

Enter the pre-tax price. GST will be added on top.

GST rate

Use a preset above or enter any rate, including state-specific or cess-inclusive rates.

Type of supply

Final price (incl. GST)

₹11,800.00

18% GST added to ₹10,000.00.

Base price
₹10,000.00
GST amount
₹1,800.00

Tax breakdown

CGST (9%)
₹900.00
SGST (9%)
₹900.00
Total GST
₹1,800.00
Total invoice value
₹11,800.00

Intra-state supply: the levy is split equally between central (CGST) and state (SGST) governments.

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About this calculator

Goods and Services Tax (GST) is charged as a percentage of a product or service’s taxable value. This calculator works in both directions: add GST to a pre-tax price to get the invoice total, or remove GST from a final price to recover the base value and the tax embedded in it. It also splits the tax into CGST, SGST or IGST depending on whether the supply is within a state or across states.

How to use this calculator

  1. Choose add or remove

    Use "Add GST" when you have a pre-tax price and need the final amount. Use "Remove GST" when you have a receipt total and need to know how much of it was tax.

  2. Enter the amount

    Make sure it matches the mode: an exclusive (pre-tax) figure for add, or an inclusive (final) figure for remove. Mixing these up is the most common GST calculation error.

  3. Select the GST rate

    Pick one of the standard slabs — 0%, 5%, 12%, 18% or 28% — or enter a custom rate if your goods attract a different or cess-inclusive rate.

  4. Set the type of supply

    Intra-state supply splits the tax into CGST and SGST. Inter-state supply charges a single IGST. The total tax is the same either way; only who collects it differs.

Formula

Adding GST: GST = Base × Rate / 100 Total = Base + GST Removing GST: Base = Total / (1 + Rate / 100) GST = Total − Base
  • Base is the taxable value of the goods or services, excluding tax.
  • Total is the invoice value including GST.
  • To remove GST you must divide, not subtract the percentage. Subtracting 18% from an inclusive price gives the wrong answer because the 18% was calculated on the smaller base figure, not on the total.
  • For intra-state supply: CGST = SGST = GST ÷ 2.
  • For inter-state supply: IGST = the full GST amount.

Worked example

Inputs

  • Base price: ₹10,000
  • GST rate: 18%
  • Supply: intra-state

Calculation

GST = 10000 × 18 / 100 = 1800 Total = 10000 + 1800 = 11800 CGST = 1800 / 2 = 900 SGST = 1800 / 2 = 900 Reversing from the total: Base = 11800 / 1.18 = 10000 ✓ Note: 11800 − 18% = 9676, which is wrong. The correct inverse is division by 1.18.

A ₹10,000 base price at 18% GST gives ₹1,800 tax — ₹900 CGST and ₹900 SGST — for a final invoice of ₹11,800.

What the result means

  • Base price is the taxable value that appears on a GST invoice before tax is applied. This is the figure a registered business records as revenue.
  • GST amount is the tax collected. A registered business collects it on behalf of the government and remits it, offsetting any input tax already paid on purchases.
  • CGST and SGST each represent half the levy on an intra-state sale — one half goes to the centre, the other to the state where the supply occurred.
  • IGST applies to inter-state supplies and is collected by the centre, then apportioned to the destination state. The amount equals what CGST and SGST would have totalled.

Related calculations

  • Switch to remove mode with the invoice total to verify the tax a supplier has charged you.
  • Compare the same base price at 12% and 18% to see the effect of a slab change on the final price.
  • Toggle between intra-state and inter-state to confirm the total tax is unchanged and only the split differs.

Frequently asked questions

How do I remove GST from a price?

Divide the inclusive price by (1 + rate/100). For an 18% rate, divide the total by 1.18. For example, ₹11,800 ÷ 1.18 = ₹10,000 base, meaning ₹1,800 was GST. Do not subtract 18% from the total — that gives ₹9,676, which is incorrect, because the tax was calculated on the base value, not on the inclusive total.

What is the difference between CGST, SGST and IGST?

CGST (Central GST) and SGST (State GST) apply to supplies within a single state and each takes half the total rate — an 18% intra-state supply is 9% CGST plus 9% SGST. IGST (Integrated GST) applies to supplies between states and is charged at the full rate as a single levy. The total tax paid is identical; only the distribution between central and state governments differs.

What are the current GST rates in India?

The main slabs are 0%, 5%, 12%, 18% and 28%. Essential items such as most unprocessed food are at 0% or 5%, standard goods and most services at 12% or 18%, and luxury or demerit goods at 28%, sometimes with an additional compensation cess. Rates are revised periodically by the GST Council, so verify the current rate for your specific HSN or SAC code.

Is GST calculated on the discounted price?

Yes. GST is charged on the transaction value after any discount shown on the invoice. If a discount is given at the time of supply and recorded on the invoice, tax applies to the reduced amount. Discounts given after the supply only reduce the taxable value if they were agreed beforehand and can be linked to specific invoices.

Does this calculator handle cess?

Not as a separate line. Certain goods such as tobacco, aerated drinks and some vehicles attract a compensation cess in addition to GST. You can enter a combined rate in the custom rate field, but the result will show the total as GST rather than splitting out the cess component.

Who has to register for GST?

In general, businesses with annual turnover above ₹40 lakh for goods or ₹20 lakh for services must register, with lower thresholds in certain special-category states. Inter-state suppliers, e-commerce operators and some other categories must register regardless of turnover. Check the current thresholds with a tax professional, as they are revised from time to time.

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