Indian GST splits into CGST and SGST within a state, or a single IGST across state lines, and input credit offsets it.
Who this is for: Invoicing correctly for intra-state and inter-state supply.
The amount, the rate, and where the supply goes
Amount and rate
Net amount (for Add) or tax-inclusive amount (for Remove/Reverse), in your local currency.
%
Under GST 2.0 (from 22 Sep 2025) the main slabs are 0, 5 and 18%, plus 40% on select sin and luxury goods; the 12% and 28% slabs were removed. 18% is the standard slab — confirm your HSN/SAC rate with CBIC.
Add treats the amount as net; Remove/Reverse treat it as tax-inclusive and extract the GST.
Supply type and credit
Intra-state splits GST into equal CGST and SGST; inter-state charges a single IGST.
GST already paid on purchases that you can offset. Leave at 0 if none.
GST Amount
180.00
Total GST on the supply, in your local currency.
Formula verified 25 September 2026
Net Price (before GST)
1,000.00
Taxable value excluding GST.
Gross Price (with GST)
1,180.00
Net price plus GST.
Net GST Liability After ITC
180.00
GST due after offsetting input tax credit (not below zero).
Intra-state splits the GST into equal CGST and SGST; inter-state charges a single IGST. Rates follow the GST 2.0 slabs; confirm your HSN/SAC rate with CBIC.
Component
Rate
Amount
CGST
9.00%
90.00
SGST
9.00%
90.00
IGST
—
0.00
Total GST
18.00%
180.00
Estimates only — not financial, tax, or professional advice.
Calculated in your browser — the numbers you enter are never sent to our servers.
What it calculates: GST Amount, Net Price (before GST), Gross Price (with GST), Net GST Liability After ITC.
Intra-state splits the rate in half; inter-state does not
A supply within a state carries CGST and SGST at half the rate each — 18% becomes 9% central and 9% state. A supply across state lines carries IGST at the full 18% instead. The total the customer pays is identical either way; what differs is which government receives it.
GST = amount x rate ; intra-state splits into CGST + SGST (half each); inter-state = IGST
This matters for invoicing rather than for pricing. An invoice showing IGST on an intra-state supply, or the reverse, is incorrect even though the amount collected is right, and it creates a mismatch in the returns of both parties.
Extracting tax from a total is division, not a percentage of it
To add 18% to 1,000 you multiply — the tax is 180. To extract 18% from an inclusive 1,180 you divide by 1.18, which gives a base of 1,000 and tax of 180. Taking 18% of 1,180 gives 212.40 and is wrong.
The mode toggle exists because both directions are needed constantly: pricing a product from a cost base uses one, and breaking down a receipt uses the other.
You pay tax on the value you added, not on the whole price
A registered business offsets the GST it paid on purchases against the GST it collected on sales, and remits only the difference. That is why GST is not a cost to a registered business in the middle of a supply chain — it is a cost to the final consumer.
The credit is conditional. It generally requires a valid tax invoice, the supplier to have actually reported and paid, and the goods or services to be used for business purposes. Blocked categories exist, and credit claimed where the supplier defaulted is commonly reversed later.
Slabs, exemptions and reverse charge sit outside this calculation
India operates several GST slabs with a compensation cess on some goods, and the classification of a specific product determines which applies. The calculator takes the rate you enter rather than guessing at an HSN classification.
Reverse charge, where the recipient rather than the supplier pays, composition scheme rates, and place-of-supply rules for services are all outside this tool. For anything beyond a straightforward computation, confirm the position with a tax professional.
Frequently Asked Questions
How do I calculate GST in India?
To add GST, multiply the net amount by the GST rate (for example 1,000 x 18% = 180). To extract GST from a tax-inclusive price, divide the gross by one plus the rate to get the net, then subtract to find the GST. The rate depends on the HSN/SAC classification of the goods or service.
How do I remove GST from a price?
Divide the tax-inclusive price by one plus the rate as a decimal. For 18%, divide by 1.18 to get the net price, then subtract the net from the gross to find the GST included. This is the Remove or Reverse mode in the calculator.
Are the GST rates in this calculator current?
The slabs it describes are the GST 2.0 ones in force from 22 September 2025: 0%, 5% and 18%, plus 40% for select sin and luxury goods, with the 12% and 28% slabs removed. The default 18% is the standard slab. What you must confirm with CBIC is the rate for your own HSN/SAC code, since special rates such as 3% on gold sit outside the main slabs.
Is GST the same on goods and services?
The mechanism is the same, but the rate depends on the specific item and its HSN code (goods) or SAC code (services). Different goods and services fall into different slabs, so always check the classification rather than assuming a single rate.
Does this calculator handle cess or the composition scheme?
No. It applies one GST rate and the standard CGST/SGST/IGST split. Compensation cess, the composition scheme, and special schemes have their own rules that this simple tool does not model — verify those separately with CBIC.
Sources & References
Figures on this page are checked against primary, authoritative sources. Links open in a new tab.
The 18% default is the standard GST 2.0 slab, not a rate for any particular good or service. Under GST 2.0 (effective 22 Sep 2025) the slabs are 0/5/18% plus a 40% rate on select sin/luxury goods; the old 12% and 28% slabs were removed (lastUpdated: 2026-06).
Intra-state GST is split equally into CGST and SGST; inter-state supplies are charged a single IGST at the full rate.
Input tax credit is treated as a simple offset and assumed to be eligible; real ITC has conditions and blocked credits.
Verify the current rate, HSN/SAC classification, and ITC eligibility with CBIC or a qualified tax professional for your supply and date.
Where it stops
The tool applies one flat rate; it does not handle cess, composition scheme, or mixed/composite supplies.
It does not validate place-of-supply rules that determine whether a transaction is intra-state or inter-state.
Reverse-charge mechanism, e-invoicing, and return-level adjustments are outside its scope.
This is not tax advice; GST rates, rules, and ITC conditions change frequently and depend on the specific supply.
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Tax rules vary by country, state, tax year, filing status, income type, deductions, and exemptions. This calculator is educational and uses the values you enter. Always verify final tax treatment with official sources or a qualified tax professional.
Published the calculator with its formula, worked example, assumptions, limitations and a bespoke guide, and added an automated formula test suite covering it.
Tested GST added to and extracted from a price, the CGST and SGST split against a single IGST charge, and the input tax credit offset.
Tested that extracting tax from an inclusive price is division rather than a percentage of the total, and that the two supply types collect the same amount.
Described the default 18% as the standard GST 2.0 slab (0, 5 and 18%, plus 40%, from 22 September 2025) instead of calling it a placeholder.
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