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Create GST invoice

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GST calculator

Enter an amount and a GST rate. You get the tax, the total and the split your invoice must show: CGST and SGST within a state, IGST between states.

The amount
Where the supply takes place

Within your state you charge CGST + SGST (half the rate each); to another state, IGST at the full rate.

GST breakdown

₹1,800.00

Taxable value
₹10,000.00
CGST @ 9%
₹900.00
SGST @ 9%
₹900.00
Total GST
₹1,800.00
Total with GST
₹11,800.00
Make this GST invoice

How GST is worked out

GST is a percentage of the taxable value, the price of the goods or services before tax. For ₹10,000 at 18%, the GST is ₹1,800 and the invoice total ₹11,800.

Which tax you charge depends on where the supply takes place. When you and your customer are in the same state, the GST splits equally into CGST (for the Centre) and SGST (for the state): ₹900 each in the example. When the place of supply is in another state, the whole ₹1,800 is IGST.

Each half is rounded to the paisa on its own, which is how a tax invoice prints it. That is why CGST and SGST on an odd amount can each round up.

Which GST rate applies

Since the GST rate changes of 22 September 2025, most goods and services are taxed at 5% or 18%, with 40% on a short list of luxury and sin goods. Special rates remain for a few items, such as 3% on gold and 0.25% on rough diamonds.

The rate follows the HSN code (goods) or SAC code (services) of what you sell. Look up yours in our HSN and SAC guide, and check the notified rate before you invoice.

What your tax invoice must show

  • Your GSTIN and, for a registered buyer, theirs.
  • The HSN or SAC code of each item.
  • The taxable value, the rate and the amount of each tax: CGST and SGST, or IGST.
  • The place of supply (state name and code) for an inter-state supply.

Last updated 2026-09-30. This calculator is a guide, not tax advice.

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. ₹5,000 × 18% = ₹900 GST, so the total is ₹5,900. Within a state that is ₹450 CGST plus ₹450 SGST.

When do I charge IGST instead of CGST and SGST?

Charge IGST when the place of supply is in a different state or union territory from your registration, and on supplies to SEZ units. Charge CGST and SGST (or UTGST) when it is in your own state.

Is the GST rate the same for CGST and SGST?

Yes. The rate is split equally: 18% GST is 9% CGST and 9% SGST; 5% GST is 2.5% each.

Can I take GST out of a price that already includes it?

Yes. Switch the calculator to “Amount includes GST”, or use the reverse GST calculator. It divides the price by (1 + rate) to find the taxable value.