GST Calculator
Reviewed by Subir Kumar Debsharma, Tax, GST and ROC professional with 20+ years of experience.
Most GST calculators online are quietly out of date. India overhauled its GST rates in September 2025, dropping the old four slabs for two standard rates plus a single high rate on luxury and sin goods, and many tools still show the old dropdown. This one uses the current slabs, adds or removes GST in either direction, splits the tax into CGST, SGST, and IGST, and handles a cess line that almost no competitor offers. It is an educational estimate. For a filing, an invoice, or a registration decision, a chartered accountant is the right person to confirm the treatment.
The base price you charge before tax.
Leave at 0 unless the item carries a cess or health levy on top of GST, as some tobacco and pan masala do.
Total price (incl. GST)
₹11,800
- GST amount
- ₹1,800
- CGST (9%)
- ₹900
- SGST (9%)
- ₹900
- Base price (excl. GST)
- ₹10,000
For a sale within your own state, GST splits in half: CGST goes to the Centre and SGST to the state, each at half the rate. An 18% supply is 9% plus 9%. Since 22 September 2025 the standard slabs are 5% and 18%, with 40% on sin and luxury goods. The old 12% and 28% slabs were removed and are kept here only for calculating pre-reform invoices.
How does the GST calculator work?
The GST calculator takes a price and a rate and works out the tax in whichever direction you need: adding GST to a base price, or stripping it out of a price that already includes it. Pick the direction, choose the type of supply, enter the amount and the rate, and it returns the GST, the CGST and SGST or IGST split, any cess, and the base and total prices. The two toggles do the work most tools skip.
The direction toggle matters more than it looks. Adding GST answers "what do I charge on top of my price," which is the seller's question. Removing GST answers "how much of this MRP is tax," which is the buyer's. They use different arithmetic, and mixing them up is the single most common GST error.
What are the current GST slabs after the 2025 reform?
India's GST now has two standard slabs, 5% and 18%, plus a 40% de-merit rate for sin and luxury goods, effective 22 September 2025 under the 56th GST Council reform. The old 12% and 28% slabs were abolished, and their items were redistributed. This is the change most online calculators haven't caught up with.
| Rate | Applies to | Status |
|---|---|---|
| 5% | Essentials and merit goods | Current standard slab |
| 18% | Most goods and services | Current standard slab |
| 40% | Sin and luxury (aerated drinks, high-end cars, tobacco from 1 Feb 2026) | New de-merit rate |
| 12% | Redistributed to 5% or 18% | Abolished 22 Sep 2025 |
| 28% | Redistributed to 18% or 40% | Abolished 22 Sep 2025 |
A handful of statutory special rates still exist outside this structure, roughly 0.25% on rough diamonds and up to 3% on gold, silver, and jewellery, which is why those appear in the rate list too. For nearly everything an ordinary buyer touches, though, the answer is now 5% or 18%.
How is GST split into CGST, SGST and IGST?
GST splits by where the buyer is: a sale within your own state is half CGST and half SGST, while a sale to another state is a single IGST at the full rate. The total tax is identical either way. Only the split and who receives it change.
Take a 26,500 rupee consulting fee at 18%. Sold within the same state, the 4,770 rupees of GST becomes 2,385 CGST for the Centre and 2,385 SGST for the state. Bill the same client in another state and the whole 4,770 is charged as IGST, which the Centre later shares with the buyer's state. The seller collects the same 4,770 rupees in both cases, which is why the split rarely changes what a buyer pays.
How do you calculate reverse GST?
Reverse GST extracts the tax already baked into a GST-inclusive price by dividing that price by 1 plus the rate as a decimal, which gives the base. For an 18% item, divide the total by 1.18; the difference is the GST. A 9,440 rupee inclusive bill works back to 8,000 rupees base and 1,440 rupees of GST.
The trap here catches almost everyone. Multiplying a GST-inclusive price directly by the rate overstates the tax, because the rate applies to the base, not to a total that already contains tax. On that 9,440 rupee bill, multiplying by 18% would wrongly suggest 1,699 rupees of GST instead of the correct 1,440. The division form avoids the mistake, and it's the version this calculator uses.
What the basic formula leaves out
The add-and-remove formula is only the surface of GST, which also runs on input tax credit, the reverse charge mechanism, the composition scheme, registration thresholds, and cess. A calculator can't decide these for you, but knowing they exist keeps you from misreading your own numbers.
| Concept | What it means |
|---|---|
| Input tax credit (ITC) | A registered business subtracts the GST it paid on purchases from the GST it collects, so tax lands only on the value it added. |
| Reverse charge (RCM) | For certain supplies, the buyer pays GST directly to the government instead of the seller. |
| Registration threshold | GST registration is required above 40 lakh turnover for goods and 20 lakh for services (half that in special-category states). |
| Composition scheme | Small businesses under 1.5 crore turnover can pay a flat 1% to 6% and skip detailed filing, but lose input tax credit. |
| Cess | An extra levy some sin goods carry on top of GST. The old compensation cess is being wound down, and tobacco and pan masala moved to 40% GST with a separate health levy from 1 February 2026. |
What this calculator does not do
It computes GST on a single amount. It does not tell you which slab a specific product falls in, because that turns on the exact HSN or SAC classification, and it does not compute input tax credit, file a return, or handle multi-item invoices. It assumes the rate you pick is correct for your good or service. Cess treatment for tobacco and pan masala is more complex than a single percentage, and the reform is still settling in, so a chartered accountant is the right person to confirm the rate and the treatment for anything you actually file. This is general education, not tax advice.
Pair this calculator with the guide
For how GST works end to end, the slab history, and the return types, read the guide to GST in India. GST sits alongside income tax in the tax concepts hub, which maps how India's direct and indirect taxes fit together, and for the direct-tax side, the income tax slab guide covers what you owe on your salary.
Frequently asked questions
What are the current GST rates in India?
India's current GST has two standard slabs, 5% and 18%, plus a special 40% de-merit rate for sin and luxury goods. This structure came from the 56th GST Council meeting and took effect on 22 September 2025, and it removed the old 12% and 28% slabs by folding those items into 5%, 18%, or 40%. A few statutory special rates survive for bullion and diamonds, around 0.25% to 3%. So for almost everything you buy today, the rate is 5% or 18%.
How do you calculate GST on a price?
To add GST, multiply the base price by the GST rate and divide by 100, then add it back. A 26,500 rupee service at 18% carries 4,770 rupees of GST, for a total of 31,270 rupees. If the sale is within your own state, that 4,770 splits into 2,385 CGST and 2,385 SGST. If it goes to another state, the whole 4,770 is charged as IGST. The calculator does both directions and both splits for you.
How do you remove GST from an inclusive price?
To remove GST from a price that already includes it, divide the inclusive price by 1 plus the rate as a decimal, which gives the base. For an 18% item, divide the total by 1.18. A 9,440 rupee GST-inclusive bill at 18% works back to a base of 8,000 rupees and 1,440 rupees of GST. The common mistake is multiplying the inclusive price directly by the rate, which overstates the tax, because the rate applies to the base, not the GST-inclusive total.
What is the difference between CGST, SGST and IGST?
CGST and SGST apply to a sale within a single state, splitting the GST in half between the Centre (CGST) and the state (SGST), so an 18% intra-state supply is 9% CGST plus 9% SGST. IGST applies to a sale between two states, charged as a single tax at the full rate, later shared between the Centre and the buyer's state. The total tax is the same either way; only the split and the destination differ.
Did the 12% and 28% GST slabs get removed?
Yes. The 56th GST Council meeting removed the 12% and 28% standard slabs with effect from 22 September 2025, leaving two standard rates of 5% and 18% and a special 40% rate for sin and luxury goods. Items that used to sit at 12% or 28% moved into 5%, 18%, or 40%. This calculator keeps 12% and 28% as selectable options only so you can still work out invoices dated before the reform.
Is GST the same as US sales tax?
No. GST is a single nationwide value-added tax collected at every stage of the supply chain with credit for tax already paid, so the final consumer bears it once. The US has no federal GST or VAT at all; instead each state, county, and city sets its own sales tax, charged only at the final sale, which is why the rate changes from one ZIP code to the next. GST is one system across India; US sales tax is thousands of local ones.
Sources
- Press Information Bureau, GST Reforms 2025 (56th GST Council decisions), pib.gov.in
- Central Board of Indirect Taxes and Customs, GST rate notifications and CGST/IGST Acts, cbic-gst.gov.in
- GST Council, 56th GST Council Meeting decisions, gstcouncil.gov.in