GST Calculator
Goods and Services Tax sits on top of almost every invoice you issue or pay in India, and the confusion usually comes from reading a tax-inclusive number as a pre-tax one. This calculator works in both directions from a single page: type a price and it adds GST, or type a bill total and it strips the tax back out. Shopkeepers, freelancers and anyone checking a quotation can use it in seconds.
Applies to FY 2025-26Last updated 12 Oct 2026
Enter values
Results
- GST at 18%
- ₹1,800.00
- Amount before GST
- ₹10,000.00
- Amount including GST
- ₹11,800.00
- CGST (9%)
- ₹900.00
- SGST (9%)
- ₹900.00
How is the GST calculated?
Enter the amount, then tell the calculator whether that figure already includes GST or sits before it. Pick the slab — 5%, 12%, 18% or 28% — and choose the supply type: intra-state splits the tax into equal CGST and SGST halves, while inter-state charges the whole thing as IGST. The results show the GST amount, the price without tax, the price with tax and the split.
Formula
Add GST: GST = net × rate ÷ 100 and gross = net + GST. Remove GST: net = gross × 100 ÷ (100 + rate) and GST = gross − net. An intra-state supply divides the tax equally into CGST and SGST; an inter-state supply charges the same total as IGST.
Example
A supplier quotes ₹10,000 before tax at 18%. GST = 10,000 × 18 ÷ 100 = ₹1,800, so the invoice becomes ₹11,800, carrying ₹900 as CGST and ₹900 as SGST. Read the same bill backwards and ₹11,800 inclusive of 18% tax holds a ₹10,000 net price plus ₹1,800 of GST. A 12% supply works the same way: ₹1,00,000 net becomes ₹1,12,000 gross, with ₹6,000 landing in each half of the split.
Things to remember
GST rates are set by the GST Council and can move at any council meeting, so confirm the slab for your product before quoting. Rates above follow FY 2025-26 — check the latest notification before filing, and remember that most essentials sit at 0% or 5% rather than 18%.
Frequently Asked Questions
What is the difference between CGST, SGST and IGST?
A sale inside one state is taxed twice at half the rate: CGST goes to the Centre and SGST to the state. A sale across state lines carries the full rate as IGST instead. The total tax is identical either way — only who receives it changes.
How do I remove GST from a total amount?
Divide the tax-inclusive price by (100 + rate) and multiply by 100 to get the net, then subtract. A ₹11,800 bill at 18% is 11,800 × 100 ÷ 118 = ₹10,000 net, which leaves ₹1,800 of GST.
Which items fall in the 28% GST slab?
The top slab covers demerit and luxury goods such as cigarettes, aerated water, luxury cars and cement, several of which also carry compensation cess. Most food grains and dairy stay at 0%, everyday items at 5%, and services at 18%.
Does an inter-state bill cost more GST?
No. Intra-state and inter-state supplies of the same goods at the same rate produce the same tax — a ₹10,000 item at 18% bears ₹1,800 either way. The difference is administrative: IGST is later apportioned between the Centre and the destination state.
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