GST — Goods and Services Tax — is India's combined indirect tax. There are five common slabs: 0%, 5%, 12%, 18%, 28%. The calculator handles all of them, in both directions.
Open the GST Calculator to convert any amount.
Two directions, two formulas
Adding GST (price is exclusive)
You see a quote of ₹10,000 + 18% GST. The total is:
total = price × (1 + GST/100)
So ₹10,000 + 18% GST = ₹11,800. (GST component: ₹1,800.)
Removing GST (price is inclusive)
You see a final price of ₹11,800 inclusive of 18% GST. The base price is:
base = total / (1 + GST/100)
So ₹11,800 / 1.18 = ₹10,000. (GST component: ₹1,800.)
The common mistake is computing 18% of ₹11,800 directly — that gives ₹2,124, which is wrong. You have to divide to back-out an inclusive amount, not multiply.
The slabs (cheat sheet for everyday items)
| Slab | Examples |
|---|---|
| 0% | Fresh milk, fresh vegetables, books |
| 5% | Tea, coffee, packaged paneer, life-saving drugs, economy flights, restaurant (non-AC) |
| 12% | Butter, ghee, cheese, mobile phones, processed food |
| 18% | Most services, software, soap, AC restaurant, hotels under ₹7,500/night, branded apparel above ₹1,000 |
| 28% | Luxury cars, motorcycles, ACs, fridges, tobacco, soft drinks |
(Slabs change every Council meeting — always confirm for tax filings.)
CGST, SGST, IGST — which one when?
- Intra-state sale: tax splits equally — CGST (half) + SGST (half). 18% becomes 9% CGST + 9% SGST.
- Inter-state sale: the entire amount is IGST. 18% becomes 18% IGST.
- Import: IGST on import.
The total tax is the same. Only the routing differs (for reconciliation between central and state governments).
Real-world examples the calculator handles
- Adding GST to a quote — vendor sent you ₹50,000 + GST; what's the total invoice?
- Splitting a receipt — your dinner receipt says ₹2,360 inclusive of 18% GST; what was the base?
- Comparing vendors — vendor A quotes inclusive, vendor B quotes exclusive. Normalize and compare.
- Reverse-engineering a discounted invoice — original ₹X, discount Y%, GST Z%, final ₹? (CalcMaster handles this chain.)
Run yours
Open the GST Calculator and stop doing this math in your head wrong.
