GST Calculator

Enter the amount, pick the GST slab and say whether the amount is before GST or already includes it. Choose within-state or inter-state supply to get the CGST and SGST halves or a single IGST line.

How to use the GST calculator

1. Amount: the price or invoice value you have.
2. GST rate: pick the slab that applies to the goods or service. The list covers 0.25%, 3%, 5%, 12%, 18%, 28% and 40%.
3. The amount is: choose “Before GST” to add tax to a price, or “GST inclusive” to take the tax out of an MRP or total that already includes it.
4. Supply: choose “Within state” for a sale where the supplier and the place of supply are in the same state or union territory, and “Inter-state” when they are in different ones.

The result shows the price with or without GST, the taxable value, the total GST, the CGST and SGST or UTGST split or the IGST amount, and the total invoice value, all to the paisa.

How GST is calculated

Adding GST to a taxable value:

• GST = taxable value × rate ÷ 100
• Invoice value = taxable value + GST

₹10,000 at 18%: GST is ₹1,800 and the invoice value is ₹11,800.

Taking GST out of an inclusive amount:

• Taxable value = inclusive amount ÷ (1 + rate ÷ 100)
• GST = inclusive amount − taxable value

₹10,000 including 18% GST: the taxable value is ₹10,000 ÷ 1.18 = ₹8,474.58, and the GST is ₹1,525.42.

The most common mistake

Subtracting 18% from an inclusive amount gives the wrong taxable value. 18% of ₹10,000 is ₹1,800, which would leave ₹8,200. But 18% GST on ₹8,200 is only ₹1,476, so the invoice would total ₹9,676, not ₹10,000. GST is a percentage of the taxable value, not of the total, so you must divide. The “GST inclusive” option does this for you. To check any split, add the GST back to the taxable value; you should get the original amount to the paisa.

CGST, SGST, UTGST and IGST

The type of GST depends on where the supply takes place:

• Intra-state supply, within one state: the tax is split equally into Central GST (CGST) and State GST (SGST). At 18%, that is 9% CGST and 9% SGST.
• Within a union territory without a legislature, such as Chandigarh or Ladakh: CGST and Union Territory GST (UTGST), again split equally.
• Inter-state supply, and imports: a single Integrated GST (IGST) at the full rate.

The total tax is the same either way. What changes is which government receives it, how it shows on the invoice and how the buyer claims input tax credit. Charging CGST and SGST when IGST was due, or the other way round, is a common error. The fix is to pay the correct tax and claim a refund of the wrong one, which takes time, so it pays to get the place of supply right on the invoice.

Examples

Amount	Rate	Mode	Supply	Taxable value	GST	Invoice value
₹10,000	18%	Before GST	Within state	₹10,000.00	₹900 CGST + ₹900 SGST	₹11,800.00
₹10,000	18%	Before GST	Inter-state	₹10,000.00	₹1,800 IGST	₹11,800.00
₹11,800	18%	GST inclusive	Within state	₹10,000.00	₹900 CGST + ₹900 SGST	₹11,800.00
₹1,000	5%	GST inclusive	Within state	₹952.38	₹23.81 CGST + ₹23.81 SGST	₹1,000.00
₹10,000	40%	Before GST	Inter-state	₹10,000.00	₹4,000 IGST	₹14,000.00

GST rates after the 2025 changes

From 22 September 2025, the GST Council simplified the rate structure. Most goods and services now fall into two main slabs:

• 5% for many everyday goods, some food items and certain services.
• 18% as the standard rate for most goods and services.
• 40% for a short list of luxury and sin goods, such as some high-end vehicles and aerated sugary drinks.

Special rates remain for some items, such as 3% on gold and silver and 0.25% on rough diamonds and some precious stones, and many essentials are exempt. The older 12% and 28% slabs were largely folded into 5%, 18% and 40%, but they are still in the calculator because a few items remain at those rates during the transition, and because you may need to check invoices issued before the change. Always confirm the current rate for your HSN or SAC code on the CBIC rate notifications or with your tax adviser.

Input tax credit

A registered business can usually claim credit for the GST it pays on purchases used in its business, and set it off against the GST it collects on sales. That makes the taxable value and the GST amount on every purchase invoice important. To claim input tax credit, the supplier must have filed the invoice in their GSTR-1, it must show in your GSTR-2B, you must have received the goods or services, and the supplier must have paid the tax. Checking the supplier’s GSTIN before you pay is a simple way to avoid losing credit. The PAN, GSTIN and IFSC validator checks the format and check digit of any GSTIN.

Invoices and rounding

A tax invoice must show the supplier’s and, for B2B supplies, the buyer’s GSTIN, the HSN or SAC code, the taxable value, the rate and amount of each tax and the place of supply. GST is calculated per line item and is usually rounded to the nearest rupee at the invoice total. If you price products as round MRP figures that include GST, use the inclusive mode to get the taxable value to enter in your billing software.

Reverse charge

For some supplies, the buyer pays the GST to the government instead of the supplier. This is called the reverse charge mechanism. It applies, for example, to legal services from an advocate to a business, goods transport agency services in many cases, and rent paid by a registered business to an unregistered landlord for commercial property. The supplier’s invoice then shows no GST, and the buyer works out the tax and pays it in cash in their return, then usually claims it back as input credit. The calculator works the same way for reverse charge: enter the invoice value as before GST, pick the rate and supply type, and the result is the tax you must pay yourself.

Composition scheme and unregistered sellers

Small businesses under the composition scheme pay tax at a flat rate on turnover, such as 1% for most traders, and cannot charge GST on their invoices or pass on input credit. Businesses below the registration threshold are not registered and do not charge GST at all. If an unregistered seller adds GST to your bill, ask for their GSTIN, because they are not allowed to collect it.

Other uses

• Checking a restaurant or online shopping bill: enter the total as GST inclusive with the rate to see whether the tax charged matches.
• Pricing a product: decide your selling price including GST and use the inclusive mode to find the taxable value to enter.
• Budgeting: add GST to a quote from a supplier or contractor to see the real cost.

For writing the invoice total in words, use the amount in words converter. To check a supplier’s bank details before paying, use the IFSC code finder.

Keep a copy of every invoice and the calculation behind it for at least the period the GST law requires, which is generally 72 months from the due date of the annual return.

The calculations run in your browser. Nothing you enter is stored or sent.

Frequently asked questions

How do I calculate GST from an inclusive amount?

Divide the amount by 1 plus the rate as a decimal. For ₹11,800 at 18%, divide by 1.18 to get a taxable value of ₹10,000; the GST is ₹1,800. Do not subtract 18% of ₹11,800, which gives the wrong figure. Choose “GST inclusive” in the calculator to do this automatically.

When do I charge CGST and SGST instead of IGST?

Charge CGST and SGST when the supplier’s location and the place of supply are in the same state. Charge IGST when they are in different states, or for imports and supplies to SEZ units. For goods, the place of supply is usually where the goods are delivered; for services, the rules depend on the type of service.

What are the current GST slabs?

Since 22 September 2025, the main slabs are 5% and 18%, with 40% for selected luxury and sin goods. Gold and silver are taxed at 3% and rough diamonds at 0.25%. Many essentials are exempt. Check the CBIC notifications for the rate on your specific HSN or SAC code.

Is GST charged on the MRP?

MRP in India already includes all taxes. The seller works out the taxable value from the MRP and pays GST on that. To see the GST inside an MRP, enter it as a GST inclusive amount with the right rate. A seller cannot add GST on top of the MRP.

How is GST rounded on an invoice?

GST is calculated to the paisa for each line, and the invoice total is usually rounded to the nearest rupee, with the rounding shown as a separate line. The calculator shows figures to the paisa so you can match each line before rounding.

Can I claim GST paid on a purchase?

If you are a registered business and the purchase is used in your business, usually yes, as input tax credit. Some items are blocked, such as most motor vehicles, food and beverages and personal-use goods. The supplier must have reported the invoice and paid the tax for your credit to be allowed.