GST calculator: enter the amount, pick the GST rate and whether the price already includes GST. For a sale within your state the tax splits equally into CGST and SGST (or UTGST); for a sale to another state it is charged as IGST. Not sure of the rate? Find it in the GST Rate Finder.
GST calculator
How GST is calculated
- Add GST: GST = amount × rate ÷ 100. Total = amount + GST. Example: ₹1,000 at 18% → GST ₹180, total ₹1,180.
- Remove GST: taxable value = inclusive amount × 100 ÷ (100 + rate). Example: ₹1,180 at 18% → taxable value ₹1,000, GST ₹180.
- Within a state: CGST and SGST (or UTGST) each take half — 18% = 9% + 9%. Between states: IGST at the full rate.
- Cess (on a few goods such as some tobacco products) is added on the same taxable value.
Which GST rate to use
From 22 September 2025 (GST 2.0) most goods and services are taxed at 5% or 18%, a short list at 40%, exempt goods at Nil, gold and silver at 3% and diamonds at 1.5% or 0.25%. The rate depends on the HSN/SAC code and the entry's conditions: look up the item in the GST Rate Finder, or see what changed in GST 2.0. For invoices dated before 22 September 2025, use the rate in force then — the free BooksOn HSN app shows the rate on any date since 1 July 2017.
Questions
How do I calculate GST on an amount?
Multiply the amount by the GST rate and divide by 100. For ₹1,000 at 18%, GST is ₹180 and the total is ₹1,180. Within a state, split it into CGST ₹90 and SGST ₹90; between states charge IGST ₹180.
How do I remove GST from a GST-inclusive price?
Divide the inclusive price by (100 + rate) and multiply by 100 to get the taxable value. For ₹1,180 at 18%: 1,180 × 100 ÷ 118 = ₹1,000, so GST is ₹180.
What is the difference between CGST, SGST and IGST?
For a sale within a state, GST is split equally into Central GST (CGST) and State GST (SGST, or UTGST in a union territory). For a sale to another state, the whole tax is Integrated GST (IGST).
Is 12% or 28% GST still used?
For most goods, no: GST 2.0 moved most 12% items to 5% and most 28% items to 18% from 22 September 2025. The calculator keeps 12% and 28% for invoices dated before that.
