GST Calculator
Calculate Goods and Services Tax (GST) for inclusive and exclusive prices.
How the GST Calculator works
Reviewed by Dinesh Babu · Last updated July 2026
This calculator works out GST for both tax-exclusive prices (add GST on top of a base amount) and tax-inclusive prices (extract the GST already contained in a total). It also splits the tax into CGST and SGST for sales within a state, or shows IGST for inter-state sales.
Under GST 2.0, effective 22 September 2025, India's slabs are 0%, 5%, 18% and 40%, with 18% as the standard rate. The earlier 12% and 28% slabs were removed and most of those goods moved to the neighbouring rates. The live slab structure is shown on the calculator.
GST is a destination-based tax collected in stages, but for a single transaction the maths is simple once you know whether your price already includes tax.
GST amounts
Exclusive: GST = Amount × rate% · Inclusive: GST = Price − Price ÷ (1 + rate%)
For intra-state sales, CGST = SGST = half the GST each. For inter-state sales, a single IGST equals the full rate.
Inclusive vs exclusive — why it matters
The single most common GST error is treating an inclusive price as if it were exclusive. If you add 18% to a price that already includes GST, you overcharge. To pull GST out of a tax-inclusive total, divide by (1 + rate/100) to get the base, and the remainder is the GST.
Retail MRPs are inclusive of GST by law, so to find the tax inside an MRP you always extract, never add. B2B quotes are often exclusive, with GST shown separately on the invoice.
CGST, SGST and IGST
- Intra-state sale (buyer and seller in the same state): GST splits equally into CGST (central government) and SGST (state government).
- Inter-state sale (different states): a single IGST applies, equal to the full GST rate.
- The total tax the customer pays is the same either way — only the split between central and state differs.
- Registered businesses can claim input tax credit on the GST they pay on purchases, so GST is effectively borne by the final consumer.
| Slab | GST amount | Total price |
|---|---|---|
| 5% | ₹50 | ₹1,050 |
| 18% (standard) | ₹180 | ₹1,180 |
| 40% | ₹400 | ₹1,400 |
Adding GST (exclusive)
A product with a base price of ₹1,000 at the 18% standard rate attracts ₹180 GST, for a total invoice of ₹1,180. Within a state this splits as ₹90 CGST + ₹90 SGST; across states it is ₹180 IGST.
Extracting GST (inclusive)
If a bill shows ₹1,180 inclusive of 18% GST, the base price is ₹1,180 ÷ 1.18 = ₹1,000 and the GST portion is ₹180. At 5%, a ₹1,050 inclusive price contains ₹50 of GST (₹1,050 − ₹1,050 ÷ 1.05).
Common mistakes to avoid
- Adding GST to an MRP or any tax-inclusive price — MRPs already include GST, so you must extract it, not add it.
- Using an outdated slab. Since GST 2.0 (22 Sep 2025) the slabs are 0%, 5%, 18% and 40%; the old 12% and 28% rates no longer exist.
- Splitting CGST/SGST on an inter-state sale — those transactions use a single IGST instead.
- Confusing the tax total: CGST + SGST together equal the full rate, not double it (9% + 9% = 18%, not 36%).
Frequently asked questions
What are the current GST slabs?+
Since GST 2.0 took effect on 22 September 2025, the rates are 0%, 5%, 18% and 40%, with 18% as the standard rate. The earlier 12% and 28% slabs were removed. The live list is shown on the calculator.
What is the difference between GST inclusive and exclusive?+
Exclusive means GST is added on top of the base price (₹1,000 + 18% = ₹1,180). Inclusive means the price already contains GST (₹1,180 includes ₹180 GST). This calculator handles both, extracting GST from inclusive prices automatically.
How do I remove GST from a total amount?+
Divide the total by (1 + rate/100) to get the base price; the difference is the GST. For example, ₹1,180 at 18% gives a base of ₹1,000 and GST of ₹180. Select 'inclusive' mode and the calculator does this for you.
What are CGST, SGST and IGST?+
For a sale within a state, GST splits equally into CGST (central) and SGST (state) — so 18% becomes 9% + 9%. For a sale between states, a single IGST applies at the full rate. The customer pays the same total either way.
Does an MRP include GST?+
Yes. By law, the maximum retail price is inclusive of all taxes, including GST. So to find the GST inside an MRP you extract it (divide by 1 + rate), you never add GST on top of an MRP.
What happened to the 12% and 28% GST slabs?+
They were removed under GST 2.0 from 22 September 2025. Most goods that were at 12% or 28% moved to the nearby 5% or 18% rates, while a few sin and luxury goods sit at the new 40% slab.
Is 18% the most common GST rate?+
Yes, 18% is the standard rate applied to most goods and services. Essentials often sit at 5% or are exempt (0%), while a small set of luxury and sin goods attract 40%.