GST calculator with the new 2026 slabs
This free GST calculator works both ways: add GST to a base price to get the final amount, or remove GST from a total to find the price before tax. It uses the latest GST 2.0 slabs (5%, 18% and 40%) introduced from 22 September 2025, and splits the tax into CGST + SGST for sales within a state, or IGST for sales between states. You can also type any custom rate — handy for older 12% or 28% invoices. Everything runs in your browser, so your figures never leave your device.
Who uses this tool
Freelancers and consultants adding GST to their invoices, small business owners verifying that a supplier's invoice has the correct GST amount, and accountants quickly back-calculating the base price from a GST-inclusive total.
How to use it
- Choose whether to add GST to a price or remove GST from a total.
- Enter the amount and pick the GST rate (or type a custom one).
- Pick within-state or between-states, then click Calculate GST.
How GST is calculated
- Add GST: GST = price × rate ÷ 100; total = price + GST. (18% on ₹1,000 → ₹180 GST, ₹1,180 total.)
- Remove GST: base = total ÷ (1 + rate ÷ 100); GST = total − base. (₹1,180 at 18% → ₹1,000 base, ₹180 GST.)
- Within a state: GST splits equally — 18% = 9% CGST + 9% SGST.
- Between states: the full rate is charged as IGST.
Frequently asked questions
What are the GST slabs in 2026?
After GST 2.0 (from 22 Sep 2025): mainly 5% and 18%, with 40% on luxury/sin goods and 0% on exempt items. Niche 3% (gold) and 0.25% (rough diamonds) continue; 12% and 28% were largely removed.
How do I remove GST from a price?
Divide the total by (1 + rate/100). For 18%, divide by 1.18. Switch this tool to "Remove GST" and it does it for you.
What's the difference between CGST, SGST and IGST?
Within a state, GST is split into CGST (centre) and SGST (state), half each. Between states, the full rate is charged as IGST. The total is the same.
Can I calculate old 12% or 28% GST?
Yes — pick "Custom rate…" and type any percentage.
Is my data sent anywhere?
No. The calculation runs entirely in your browser; nothing you enter is uploaded.