Boond
The two formulas
Adding GST to a price before tax:
GST = price × rate ÷ 100
Removing GST from a price that already includes it:
Price before GST = total ÷ (1 + rate ÷ 100)
The common mistake is taking 18% off a GST-inclusive bill. 18% of ₹1,180 is ₹212.40, but the GST inside ₹1,180 is only ₹180.
Quick answers
- 18% GST on ₹1,000
- 18% GST on ₹10,000
- 5% GST on ₹1,000
- 5% GST on ₹10,000
- 40% GST on ₹1 lakh
- All amounts
Questions
Which GST rate applies to my item?
Since September 2025 most goods and services fall under 5% or 18%, with 40% for a short list of luxury and sin goods and special low rates for gold and stones. Rates change by notification, so check the latest CBIC rate list for your HSN or SAC code.
Why split into CGST and SGST?
Inside one state, the tax is shared equally by the Centre (CGST) and the state (SGST), so a bill shows both halves. Across states, the Centre collects it all as IGST and settles with the states.
Does Boond save what I type?
No. The maths runs in your browser. Nothing is sent anywhere.
Boond is a calculator, not tax advice. Rounding on real invoices can differ by a paisa.