Your figures
The split
- Taxable value
- ₹10,000.00
- CGST (9%)
- ₹900.00
- SGST (9%)
- ₹900.00
- Total GST
- ₹1,800.00
- Total payable
- ₹11,800.00
Need this on a document? Make a GST invoice with the same split, your GSTIN and the place of supply on it.
The arithmetic, as the rules actually write it
Taking GST out of an inclusive amount
The instinct is to subtract the percentage, and it is wrong every time. Rule 35 of the CGST Rules gives the formula: where the value of supply is inclusive of tax, the tax amount is
(value inclusive of tax × rate of tax) ÷ (100 + sum of the applicable rates)
The word doing the work is sum. The denominator is 100 plus the total of all the applicable rates, while the numerator is the rate of the single head you are computing. On a ₹1,18,000 intra-State supply at 18%:
- CGST = 1,18,000 × 9 ÷ 118 = ₹9,000
- SGST = 1,18,000 × 9 ÷ 118 = ₹9,000
- Taxable value = ₹1,00,000
Note the denominator is 118, not 109 — it uses the combined 18%, not the 9% of the head being calculated. Subtracting 18% instead would have given ₹96,760 and a tax figure out by ₹3,240.
The Rules contain a worked example of the same operation: Rule 31A(2) values a lottery supply at 100/140 of the face value, which is the inclusive back-calculation at a 40% rate.
What the rates are now
Most calculators still offer 5, 12, 18 and 28. That structure ended on 22 September 2025. The 56th GST Council meeting of 3 September 2025 collapsed it, and Notification 09/2025-Central Tax (Rate) gave effect to the change with seven schedules of central tax — 0.125%, 0.75%, 1.5%, 2.5%, 9%, 14% and 20% — which double, on an intra-State supply, to these combined rates:
| Combined | What it covers |
|---|---|
| 0.25% | Rough diamonds and similar. |
| 1.5% | Cut and polished diamonds. |
| 3% | Gold, silver and other precious metals. |
| 5% | The merit rate. |
| 12% | Survives only for specific brick entries — fly ash bricks and blocks, building bricks, bricks of fossil meals — notified separately by 14/2025-CT(R). |
| 18% | The standard rate, and the default for services. |
| 40% | Sin and luxury goods, and services such as betting and gambling. Also the statutory maximum. |
The 28% schedule held pan masala and tobacco after September 2025 and was itself omitted with effect from 1 February 2026. Compensation cess is now Nil throughout — Notification 03/2025-Compensation Cess (Rate) took the pan masala and tobacco entries to Nil from that date. What replaced it is not GST: pan masala carries the Health Security se National Security Cess, levied per machine installed rather than on what is produced, and tobacco carries an additional Central Excise Duty. Neither belongs in a CGST, SGST or IGST field on an invoice.
Which two heads, and why
Sections 7 and 8 of the IGST Act decide it, by comparing the location of the supplier with the place of supply. Same State or Union territory, and it is intra-State: CGST and SGST, half the rate under each head. Different, and it is inter-State: IGST at the full rate.
Neither of those is the customer’s billing address. For goods that move, Section 10(1)(a) fixes the place of supply where the movement terminates for delivery to the recipient, and Section 10(1)(b) deals with bill-to/ship-to, where the goods are deemed received by the third person. Getting it wrong does not just misprint a label — it pays the tax to the wrong government, and unwinding that is slow.
In Union Territories without a legislature the second head is UTGST rather than SGST. The arithmetic is unchanged.
Discount first, then tax
Section 15(3) excludes from the value of supply a discount given before or at the time of supply where it is duly recorded in the invoice. So a discount shown on the face of the invoice comes off before the tax is worked out. Rule 46(k) then requires the invoice to print the taxable value “taking into account discount or abatement, if any”, separately from the rate at clause (l) and the tax amount at clause (m).
Rounding
Section 170 requires the amount of tax, interest, penalty, fine or any other sum payable or refundable under the Act to be rounded to the nearest rupee, with fifty paise and above treated as a whole rupee. What the section does not settle is the level at which that happens — per line, per tax head, or only at the return and payment stage — and no circular resolves it.
The practical answer is to work to the paisa and round the tax heads once, at the invoice level. Line-by-line rounding is what produces the small mismatches that get e-invoices rejected. The e-invoice schema allows a round-off adjustment between −99.99 and +99.99 on the invoice total for exactly this reason. This calculator rounds every figure to the paisa and tells you when the parts do not add back to the inclusive amount you typed, rather than quietly forcing them to.
If you round the printed total, remember that the amount in words has to move with it — the figure, the words and the return all have to say the same thing.
More invoice formats and free tools
GST invoice format
Every particular Rule 46 requires on a tax invoice, and what happens when one is missing.
GST invoice generator
Make a GST tax invoice with the CGST/SGST or IGST split worked out. No account, no invoice limit.
Proforma invoice format
An offer, not a tax invoice: no GST payable and no input tax credit against it.
Quotation format
Quote a price with a validity date, and know when a quotation becomes a contract.
Delivery challan format
Rule 55: moving goods without a supply, in triplicate, with the right markings.
UPI QR generator
A scannable UPI QR from a VPA and an amount, built to the NPCI link format in your browser.
Amount in words
A rupee figure written out in the Indian system, with paise, ready for a cheque or an invoice.
Frequently asked questions
- How do I remove GST from an inclusive amount?
- Divide, do not subtract. Rule 35 of the CGST Rules gives the formula: the tax amount equals the value inclusive of tax multiplied by the tax rate, divided by 100 plus the sum of the applicable rates. On ₹1,18,000 inclusive at 18% intra-State, CGST is 1,18,000 × 9 ÷ 118 = ₹9,000 and SGST the same. Taking 18% off ₹1,180 gives ₹967.60, which is wrong by ₹32.40.
- Is 12% GST still a thing?
- Almost never. The 56th GST Council meeting of 3 September 2025 collapsed the four-slab structure, and Notification 09/2025-Central Tax (Rate) gave effect to it from 22 September 2025: 5% merit, 18% standard, 40% for sin and luxury goods, plus the narrow schedules at 0.25%, 1.5% and 3%. A 6% central rate (12% combined) survives separately for fly ash bricks, building bricks and similar entries under Notification 14/2025-CT(R). The 28% schedule was omitted with effect from 1 February 2026.
- Why is 40% the highest possible rate?
- Because of the statutory ceilings. Section 9(1) of the CGST Act caps central tax at 20%, and Section 7(1) of the UTGST Act does the same for Union territory tax; Section 5(1) of the IGST Act caps integrated tax at 40%. A 40% intra-State supply is 20% + 20%, which is the ceiling in both directions.
- CGST + SGST or IGST — how is that decided?
- By Sections 7 and 8 of the IGST Act, comparing the location of the supplier with the place of supply — not by the customer’s billing address. Section 8 makes it intra-State where both are in the same State or Union territory; Section 7 makes it inter-State otherwise. For goods that move, Section 10(1)(a) puts the place of supply where the movement terminates for delivery to the recipient.
- When is it UTGST rather than SGST?
- Only in Union Territories without a legislature — Chandigarh, the Andaman and Nicobar Islands, Lakshadweep, Dadra and Nagar Haveli and Daman and Diu, and Ladakh. Delhi, Puducherry and Jammu and Kashmir have legislatures and are treated as States for GST, so supplies there carry CGST + SGST. The arithmetic is identical either way: half the rate under each head.
- Should I round the tax to the nearest rupee?
- Section 170 of the CGST Act requires amounts of tax, interest, penalty, fine, refund or any other sum payable under the Act to be rounded to the nearest rupee, treating 50 paise and above as a rupee. What it does not say is whether that applies per line, per tax head, or only at the return and payment stage, and no CBIC circular resolves it. This calculator works to the paisa and shows you the difference; the practical convention is to round the tax heads at the invoice level, which is what the e-invoice schema’s round-off field is for.
- Do I still need to add compensation cess?
- No, not on anything issued now. Compensation cess was reduced to Nil across the specified goods from 22 September 2025, and Notification 03/2025-Compensation Cess (Rate) took the remaining pan masala and tobacco entries to Nil from 1 February 2026. What replaced it on sin goods is not GST — pan masala carries the Health Security se National Security Cess, levied per machine installed rather than on output, and tobacco carries an additional Central Excise Duty — and neither belongs in a CGST, SGST or IGST field on your invoice.