🧾 GST Calculator

Add GST to a pre-tax amount, or work backwards from a GST-inclusive total to find the base amount and the tax inside it.

Free Instant results No sign-up needed
GST Details
₹100 ₹10,00,000
₹10,000
Net amount GST amount
Net amount (excl. GST)
₹10,000
GST amount
₹1,800
Total amount
₹11,800
CGST (50%)
₹900
SGST (50%)
₹900
Effective rate
18.0%
GST Slab Reference
5%
Essential goods — food grains, medicines, low-cost restaurants
12%
Processed foods, business class hotels, electronics accessories
18%
Standard services, most manufactured goods, telecom
28%
Luxury goods, automobiles, tobacco, high-end hotels
What This Tool Does

Add GST: Takes a pre-tax amount and adds GST at 5%, 12%, 18% or 28% to give the final payable total.

Remove GST: Takes a GST-inclusive total and works backwards to the base amount and the tax within it.

CGST and SGST split: Shows the tax divided equally into CGST and SGST, which is how an intra-state supply is reported.

What is GST?

Goods and Services Tax is the indirect tax applied to most goods and services sold in India. It replaced a layered set of central and state taxes with a single structure charged at each stage of supply.

For an intra-state sale the tax is split into CGST, collected by the centre, and SGST, collected by the state. Each takes half. For a sale between states, a single IGST is charged instead.

Exclusive and Inclusive Calculations

Adding GST is straightforward: multiply the base amount by the rate and add it on. An 18% rate on ₹10,000 adds ₹1,800, giving ₹11,800.

Removing GST is the direction people get wrong. You cannot subtract 18% from an inclusive total. You divide by 1.18 instead. So ₹11,800 inclusive of 18% GST contains a base of ₹10,000 and tax of ₹1,800. Subtracting 18% of ₹11,800 would wrongly give ₹9,676.

How to Use It

  1. Enter the amount you are working from.
  2. Pick the applicable rate: 5%, 12%, 18% or 28%.
  3. Choose Add GST if your amount is before tax, or Remove GST if it already includes tax.
  4. Read the base amount, the GST amount and the total.
  5. Use the CGST and SGST rows if you need the split for an intra-state invoice.

The Rate Slabs

  • 5% is typically applied to essential goods and several mass-consumption items.
  • 12% covers a range of processed goods and some services.
  • 18% is the most common slab and applies to a large share of goods and services.
  • 28% applies to luxury and demerit categories, sometimes with an additional cess.

Limitations You Should Know

  • Only the four main slabs are offered. Custom or nil rates cannot be entered.
  • The CGST and SGST split assumes an intra-state supply. IGST is not modelled.
  • Compensation cess on items such as tobacco or large vehicles is not included.
  • Reverse charge, input tax credit and composition scheme rules are outside the scope of this page.
  • Rate classification for a specific product or service is a matter for the GST schedules, not this calculator.

Accuracy and Processing

The arithmetic runs in your browser and nothing you type is transmitted. Results are shown to two decimal places. For filing or invoicing decisions, confirm the applicable rate and treatment with a tax professional.

GST Calculator FAQ

How do I remove GST from an inclusive amount?

Divide the total by one plus the rate as a decimal. For 18 percent GST, divide the total by 1.18. Do not subtract 18 percent from the total, which is the common mistake and gives the wrong answer.

How do I add GST to an amount?

Multiply the base amount by the rate and add it on. At 18 percent, a base of 10,000 attracts 1,800 in GST for a total of 11,800.

What are CGST and SGST?

For a supply within a single state, GST is split equally between CGST, collected by the central government, and SGST, collected by the state. Each takes half the total tax. For a supply between states, a single IGST is charged instead.

Which GST rate applies to my product?

Rate classification depends on the GST schedules for your specific goods or service. This calculator applies whichever of the four main slabs you select; it cannot determine the correct slab for you.

Does this calculator handle IGST or cess?

No. The split shown assumes an intra-state supply, so IGST is not modelled, and compensation cess on items such as tobacco or large vehicles is not included.

Can I enter a custom GST rate?

No. Only the four main slabs of 5, 12, 18 and 28 percent are available on this page.

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