GST Calculator
Add GST to a net price or reverse GST out of an inclusive total, with an instant CGST, SGST, UTGST or IGST breakup at India's GST 2.0 rates. Free, no sign-up, runs entirely in your browser.
Enter 0 to 999,999,999,999.99, with up to 2 decimal places.
Optional: 0 to 100%, with up to 6 decimal places. Clear to use the selected preset.
Invoice value (gross)
Figures rounded to 2 decimals (paise). Each tax component is rounded separately, with half a paise rounded up. Add mode sums the rounded components. Reverse mode preserves your total and assigns the remaining paise to the net amount, so a rounded invoice may not be reconstructed exactly. No cess is included.
How to calculate GST in India
GST is charged on the taxable (net) value of a supply. To add GST, multiply the net amount by (1 + rate ÷ 100): a ₹10,000 service at 18% becomes an invoice value of ₹11,800, of which ₹1,800 is tax. This online GST calculator does the multiplication for you and also shows how the tax splits between the central and state governments.
For supplies within a single state, GST divides equally between CGST and SGST (an 18% slab means 9% + 9%). For supplies within a union territory without its own legislature, select CGST + UTGST. Inter-state supplies generally use IGST. Select the tax treatment that applies under the place-of-supply rules; this calculator does not determine the legal classification of a transaction.
Reverse GST calculator: taking GST out of an inclusive price
A reverse GST calculation starts from a price that already includes tax and works backwards to the net amount. Divide by the same factor you would multiply by: Net = Inclusive ÷ (1 + rate ÷ 100). For a ₹11,800 bill at 18%, 11,800 ÷ 1.18 = ₹10,000 net, and the difference of ₹1,800 is the GST. Switch the calculator to Reverse GST mode, enter the inclusive figure, and the net amount and tax appear instantly.
Reverse GST comes up more often than people expect: a vendor quotes "₹5,900 all inclusive" and you need the taxable value for your books, a retail MRP has to be split for a tax invoice, or an expense claim needs the GST component separated so input tax credit can be claimed on it. The common mistake is to take 18% of the inclusive price, which overstates the tax; ₹11,800 × 18% is ₹2,124, not ₹1,800.
GST slabs in India (GST 2.0, effective 22 Sep 2025)
| Rate | Commonly applies to |
|---|---|
| 0% | Fresh food grains, milk, healthcare and education services (exempt or nil-rated) |
| 0.25% / 3% | Rough diamonds; gold, silver and articles of jewellery |
| 5% | Essentials and most mass-consumption goods (the GST 2.0 "merit" slab) |
| 18% | Standard rate for many taxable goods and services; classification determines the applicable rate |
| 40% | Specified demerit and luxury goods; check the item-specific notification and effective date |
GST 2.0 (56th GST Council meeting) rationalised the old four-slab structure into two main slabs from 22 September 2025. Some items moved between slabs. Always confirm the current HSN or SAC classification for your goods or services.
Sources checked 7 September 2026: GST Council guidance on the 2025 rate changes and CBIC guidance on CGST, SGST, UTGST and IGST. The rate table is a summary, not a complete HSN or SAC classification. Confirm the applicable notification and effective date before using a rate.
GST calculation examples
| Net amount | Rate | GST | Intra-state split | Invoice value |
|---|---|---|---|---|
| ₹1,000 | 5% | ₹50 | CGST ₹25 + SGST ₹25 | ₹1,050 |
| ₹5,000 | 18% | ₹900 | CGST ₹450 + SGST ₹450 | ₹5,900 |
| ₹25,000 | 18% | ₹4,500 | CGST ₹2,250 + SGST ₹2,250 | ₹29,500 |
| ₹1,00,000 | 18% | ₹18,000 | CGST ₹9,000 + SGST ₹9,000 | ₹1,18,000 |
| ₹1,00,000 | 40% | ₹40,000 | CGST ₹20,000 + SGST ₹20,000 | ₹1,40,000 |
Reading the table backwards gives the reverse GST figures: an inclusive ₹5,900 at 18% contains ₹900 of tax on a ₹5,000 net value. If you need the invoice itself, the GST invoice template builds a tax invoice PDF with CGST, SGST and IGST fields, and the number to words converter writes the total in words for the "amount in words" line.
Frequently asked questions
How do I calculate GST on an amount?
GST amount = Net amount × rate ÷ 100, and the invoice value is the net amount plus GST. For a net amount of ₹1,000 at 18% GST, the GST is ₹180 and the invoice value is ₹1,180. If goods move within one state, the ₹180 splits into CGST ₹90 and SGST ₹90; for inter-state supply it is charged as IGST ₹180.
How does a reverse GST calculator work?
A reverse GST calculation takes the tax out of a price that already includes it. Net amount = Inclusive amount ÷ (1 + rate ÷ 100). For ₹1,180 inclusive of 18% GST: 1,180 ÷ 1.18 = ₹1,000 net, and the GST component is ₹180. Switch this calculator to Reverse GST mode to do it in one step.
What is the difference between CGST, SGST and IGST?
For intra-state supplies in a state, the GST rate splits equally into CGST and SGST, e.g. 18% = 9% + 9%. For supplies within a union territory without its own legislature, use CGST and UTGST. Inter-state supplies generally use IGST at the full rate. Rounding each tax component can cause a one-paise difference in the total.
Which GST rate should I use?
The main GST 2.0 rates are 5% and 18%, with 40% for specified demerit goods and separate rates for certain other supplies. Nil-rated and exempt supplies do not attract GST. Choose the rate from the notification for your HSN or SAC code and invoice date; the presets are not a complete classification guide.
Is this GST calculator updated for GST 2.0?
Yes. Presets include 0%, 0.25%, 3%, 5%, 18% and 40%. The main GST 2.0 rate changes took effect on 22 September 2025, with some goods following different dates. For another applicable rate, including 12% or 28% on an older invoice, use the custom rate field. This tool does not calculate cess.
Is this GST calculator free?
Yes. It is completely free and requires no sign-up. The calculator processes your amounts locally in your browser without sending them to a calculation server. Advertising and optional feedback use external services described in our privacy policy.