Free GST calculator
Add GST to a base amount, or extract GST from an inclusive price — with the CGST/SGST or IGST split shown correctly. Works entirely in your browser.
How GST is calculated
Adding GST (exclusive price): GST = base amount × rate. A ₹10,000 supply at 18% carries ₹1,800 of GST, invoice total ₹11,800.
Extracting GST (inclusive price): base = inclusive ÷ (1 + rate). From an ₹11,800 inclusive price at 18%, the base is ₹10,000 and the GST is ₹1,800.
The split: within a state, GST divides equally into CGST and SGST (9% + 9% at the 18% rate). Between states, the whole amount is IGST. The rate is the same either way — only the destination of the tax differs.
Current GST rates in India
Under the GST 2.0 rate structure, the main slabs are 0%, 5%, 18% and 40%, with special rates (0.25%, 3%) for specific goods. The earlier 12% and 28% slabs apply to older documents — which is why the calculator keeps them available.
Want GST calculated automatically on every invoice? 24eTax applies the right rate, the right split and line-level rounding on every bill you raise — free for up to 50 invoices a month. Try 24eTax Free →
Frequently asked questions
How do I remove GST from an inclusive amount?
Divide by 1 + rate. For 18%: inclusive ÷ 1.18 gives the base amount; the difference is the GST. Choose "With GST" above and the calculator does exactly this.
When is it CGST+SGST and when is it IGST?
It depends on the place of supply: supplies within one state charge CGST + SGST (half the rate each); supplies between states charge IGST at the full rate. The total tax is identical.
Which GST rate applies to my product?
Rates are set per HSN/SAC code. Check your item's code and its current notified rate — inside 24eTax, items carry their HSN and rate so every invoice applies the right one automatically.
Is this calculator exact for invoicing?
It rounds to the paisa the way GST invoices should. On real invoices, rounding is applied line by line and the total is rounded to the rupee — 24eTax does that automatically on every bill.
Start free — bill, account and prepare GST today
14-day full-featured trial. No card. Works on your phone and in the browser.
Start Free