CGST + SGST, CGST + UTGST, or one IGST line
GST Calculator (India)
Press Add GST, Remove GST or Work back from GST and type one figure: the taxable value, the tax and the total all follow. Choose your own state and the place of supply and the same rate is shown the way it has to appear on the invoice — split into CGST and SGST, split intoCGST and UTGST where the supply lands in a Union territory without a legislature, or charged as a single IGST line into another state. The slabs since 22 September 2025 are 0%, 5%, 18% and 40%, and any other rate can be typed in. Free, no signup, and nothing leaves your browser.
Calculated in this browser. Nothing is uploaded or stored.
The three GST formulas
Any GST sum is one of three, depending on which figure you start with. The rate is written as a percentage, so an 18% rate is 18.
- Add GST to a taxable value
- GST = taxable value × rate ÷ 100, and total = taxable value + GST. In one step, total = taxable value × (1 + rate ÷ 100).
- Remove GST from a total
- GST = total × rate ÷ (100 + rate), and taxable value = total − GST. In one step, taxable value = total ÷ (1 + rate ÷ 100).
- Work back from the GST amount
- Taxable value = GST × 100 ÷ rate, and total = taxable value + GST. At a 0% rate there is nothing to work back from.
The mistake to avoid is taking the rate off a total as if it were the taxable value. 18% of ₹47,200.00 is ₹8,496.00, but the GST inside ₹47,200.00 is ₹7,200.00: the rate applies to the value before tax, so removing it means dividing, not subtracting a percentage.
The same supply, intra-State and inter-State
One ₹40,000.00 supply at 18%, priced once for a customer in the supplier’s own state and once for a customer in another. The total is identical; what changes is how the tax is shown.
| Supply | Tax | Taxable value | Tax | Total |
|---|---|---|---|---|
| Place of supply: Maharashtra | CGST 9% + SGST 9% | ₹40,000.00 | ₹3,600.00 + ₹3,600.00 | ₹47,200.00 |
| Place of supply: Karnataka | IGST 18% | ₹40,000.00 | ₹7,200.00 | ₹47,200.00 |
| Place of supply: Lakshadweep | CGST 9% + UTGST 9% | ₹40,000.00 | ₹3,600.00 + ₹3,600.00 | ₹47,200.00 |
The first row splits because the place of supply is the supplier’s own state. The second charges one integrated tax. The third is the same split as the first, but the state-level half is Union territory tax rather than State tax, because the supply lands in a Union territory without a legislature.
What decides the split
The place of supply, compared with the state the supplier is registered in. Same state is an intra-State supply: the rate is halved between the centre and the state, so 18% is charged as CGST 9% and SGST 9%. A different state is an inter-State supply: the full rate is charged once, as integrated tax. That single comparison is the whole of the CGST/SGST-versus-IGST question, and it is why the two states are fields on the calculator rather than something worked out behind the scenes.
A Union territory without a legislature charges Union territory tax in place of State tax, so the second half is UTGST rather than SGST. Where a territory has its own legislature, State tax applies as normal. The calculator names the second half from the place of supply you choose.
Two halves are each rounded on their own, so CGST and SGST always match to the paisa. Rounding the whole rate once and halving it can leave half a paisa on each side, which is not an amount either tax can be — the same rule the invoice generator applies to every line.
The rates since 22 September 2025
The 56th GST Council reduced the structure to 5% and 18%, with a 40% rate on demerit goods. The 12% and 28% slabs no longer apply. This calculator offers 0%, 5%, 18% and 40%, and any other rate can be typed in when your classification requires one.
The rate is the thing to confirm: which slab applies to what you sell is a classification question, and it is answered by the notifications and by your own records, not by a calculator.
What this is not
This works out the tax on the figure, rate and places you give it. It does not classify your goods or services, decide the place of supply for you, apply reverse charge, verify a GSTIN with the GST portal, or raise an invoice return — and it is not tax advice. The place of supply is not always the customer’s address and the rules differ for goods and for services, so it is stated rather than inferred. For an export it does the arithmetic at the rate you choose and nothing more: whether integrated tax is paid or the supply is made under a bond or letter of undertaking is a matter for you or your chartered accountant.
The invoice particulars, the state codes and the UTGST list were checked on 14 September 2026 against rules 46 and 48 of the CGST Rules as published by CBIC, the GSTN e-invoice master codes, and the UTGST Act, 2017. The rates reflect the 56th GST Council decisions effective 22 September 2025.