GST Calculator
Add GST to a price or take it out of an inclusive one, at the 2025 rates.
Inputs
- Taxable value₹10,000(85%)
- GST₹1,800(15%)
- Taxable value
- ₹10,000
- Total
- ₹11,800
- Rate
- 18%
Use this calculator on your own site
Free embed
- Two lines of HTML, unlimited views
- Shows a small CalculateEveryday bar, with a credit link under the calculator
What each GST input means
- Amount
- The price you have: before tax if it comes from a quote or a B2B invoice, after tax if it is a shop price or MRP.
- GST rate
- The GST rate for the item: 5% or 18% for most goods and services since 22 September 2025, 40% for the short list of sin and luxury goods. The rate follows the item's HSN or SAC code, not the seller.
- Amount is
- Choose inclusive when the price already contains GST, to find the tax inside it; exclusive when you want to add GST on top.
GST formula
Exclusive: GST = Amount × Rate; Total = Amount + GST. Inclusive: Base = Amount ÷ (1 + Rate); GST = Amount − Base
When a price is quoted before tax, GST is simply the rate times the amount, added on top. When a price already includes GST, as shop prices and MRPs do, the tax can't be found by taking the rate off the total: ₹1,180 including 18% GST hides ₹180 of tax, not ₹212.40. The taxable value is the total divided by one plus the rate, and the tax is the difference. Since the GST reform of 22 September 2025 most goods and services fall in two slabs, 5% and 18%, with a 40% rate for a short list of sin and luxury goods. Within a state the tax is split equally into central and state GST; between states it is charged as integrated GST at the full rate, so the arithmetic is the same either way.
GST worked example
₹10,000 exclusive of 18% GST adds ₹1,800 in tax for a total of ₹11,800. Switch to inclusive with ₹11,800 and the calculator splits it back into ₹10,000 of taxable value and ₹1,800 of GST, the split a tax invoice must show.
More GST examples
A shelf price of ₹1,180 including 18% GST divides by 1.18 to ₹1,000 of taxable value, so the tax inside it is ₹180, not the ₹212.40 you'd get by taking 18% of the total.
At the 5% merit rate, ₹2,000 before tax adds ₹100 of GST, ₹2,100 in all. Sold within one state, that ₹100 appears on the invoice as ₹50 central GST and ₹50 state GST.
Where the GST calculator can give the wrong answer
- Since the GST reform of 22 September 2025 the standard structure is two slabs, 5% (merit) and 18%, plus a 40% special rate on select sin and luxury goods; the old 12% and 28% slabs no longer apply generally.
- Compensation cess isn't modelled. It still applies to cigarettes, chewing tobacco, unmanufactured tobacco and beedi, which stayed on their pre-reform rates and cess until a further notified date, so this won't match invoices for those products.
- The central/state (CGST + SGST) or integrated (IGST) split isn't shown; it doesn't change the total.
- Reverse charge, the composition scheme, and TCS or TDS under GST aren't handled; this is the straight percentage calculation.
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GST reference table
| Rate | What it covers |
|---|---|
| 5% | Essentials and daily-use items (the merit rate) |
| 18% | The standard rate for most goods and services |
| 40% | A short list of sin and luxury goods and services, such as aerated drinks, cars over 1500cc, motorcycles over 350cc, betting and gambling |
| Pre-reform rate plus cess | Cigarettes, chewing tobacco, unmanufactured tobacco and beedi, until a further notified date |
GST FAQ
- Inclusive. Retail prices and MRPs in India include GST, so choose 'Inclusive of GST' to work back to the pre-tax value. Business quotes are usually exclusive, with GST added on top.
- Since the GST 2.0 reform of 22 September 2025, most goods and services fall in two slabs: 5% for essentials and daily-use items, and 18%, the standard rate. A 40% special rate applies to a short list of sin and luxury goods and services, such as aerated drinks, cars over 1500cc, motorcycles over 350cc, and betting and gambling. A few tobacco products are still on pre-reform rates plus compensation cess. Check the HSN or SAC classification for your item; the wrong rate is a compliance problem, not a calculator one.
- Divide by one plus the rate, then subtract. At 18%, ₹1,180 ÷ 1.18 = ₹1,000, so the GST is ₹180. Taking 18% of ₹1,180 gives ₹212.40, which is too much, because the 18% was charged on ₹1,000, not on ₹1,180.
- They were folded into the 5% and 18% slabs from 22 September 2025, with a small group of items moved to the new 40% rate. An item that was 12% or 28% before needs its new rate checked by its classification.
- The same tax split two ways. For a sale within a state, half the rate is central GST and half state GST, so 18% appears as 9% + 9%. For a sale between states, the full 18% is integrated GST. The amount you pay is identical.