GST Calculator
Add or remove GST from an amount and see the CGST/SGST split.
- Base amount
- ₹10,000.00
- GST
- ₹1,800.00
Intra-state split: CGST ₹900.00 + SGST ₹900.00. For an inter-state supply the same total is charged as a single IGST instead. The applicable rate depends on the goods'/services' HSN/SAC classification — verify against the current CBIC schedule.
Independent · No commissions · No fund-house data — how the numbers are computed
How it works
This calculator adds GST to a base amount or removes it from a GST-inclusive one. In add mode, enter the pre-tax amount and rate to get the GST and total; in remove mode, enter the final price and it backs out the base — useful for finding the pre-tax value inside an invoice or MRP-style price. It also splits the GST into its CGST and SGST halves for an intra-state supply.
The rate options are 5%, 18% and 40% — the slabs in force since the GST rate rationalisation of 22 September 2025 ("GST 2.0"), which folded most of the old 12% and 28% categories into 5% and 18% and introduced a 40% rate for luxury and sin goods. Which rate applies to a given good or service depends on its HSN/SAC classification under the current CBIC schedule.
Within a state, the tax is charged as equal halves of CGST (central) and SGST (state); across states, the same total is charged as a single IGST. The arithmetic of removing GST is the part people most often get wrong: an 18% GST inside a ₹118 price is ₹18, not 18% of ₹118.
Add: GST = Base × r/100, Total = Base × (1 + r/100). Remove: Base = Total / (1 + r/100)Base is the pre-GST amount, r the GST rate in percent, Total the GST-inclusive price. For an intra-state supply the GST splits equally: CGST = SGST = GST/2; inter-state it is levied as one IGST of the same total.
Frequently asked questions
What are the GST slabs after the 2025 rate change?
The GST rate rationalisation effective 22 September 2025 — widely called GST 2.0 — restructured the slabs to principally 5%, 18% and 40%, as this calculator offers. The old 12% and 28% slabs were largely folded into 5% and 18% respectively, and a new 40% rate was created for luxury and sin goods such as tobacco products and high-end cars. The rate for any specific item follows its HSN/SAC classification in the CBIC schedule.
How do I remove GST from a price that includes it?
Divide the inclusive price by one plus the rate: base = total ÷ (1 + rate/100). For a ₹1,180 price carrying 18% GST, the base is 1,180 ÷ 1.18 = ₹1,000 and the GST is ₹180. The common mistake is taking 18% of the inclusive price (₹212.40), which overstates the tax — the percentage applies to the base, which is smaller than the final price.
What is the difference between CGST, SGST and IGST?
They are the same tax split by jurisdiction. On a supply within one state, GST is levied as two equal halves — CGST to the centre and SGST to the state — so an 18% rate is collected as 9% + 9%. On a supply between states, the full amount is levied as a single IGST at the same total rate, which the centre later apportions. The buyer's total tax is identical either way.
Is GST charged on the base price or the total?
GST is charged on the taxable value — the base price before tax — not on the tax-inclusive total. An invoice shows the base, then GST at the applicable rate on that base, and their sum as the amount payable. That is why a quoted "price plus GST" and a tax-inclusive MRP-style price differ: the same 18% rate produces ₹18 of tax on a ₹100 base, making the total ₹118.