GST Calculator
Add GST to an amount or extract it from a GST-inclusive one, with the CGST and SGST split for an intra-state supply or IGST for an inter-state one.
Free · No sign-up · Nothing leaves your browser · Figures reviewed 22 September 2026
Your details
IGST if the supply crosses a state boundary; CGST and SGST if it does not.
GST to add
₹1,800.00
₹10,000.00 before tax, ₹11,800.00 after.
- Taxable value · 85%
- GST · 15%
The invoice
- Taxable value
- ₹10,000.00
- GST at 18%
- ₹1,800.00
- Total
- ₹11,800.00
Intra-state supply
- CGST at 9%
- ₹900.00
- SGST at 9%
- ₹900.00
- Total GST
- ₹1,800.00
Split equally between central and state GST when supplier and place of supply are in the same state. Both halves appear as separate lines on the invoice.
The reverse calculation
- From an inclusive amount₹10,000.00 inclusive is ₹8,474.58 before tax
- ÷ 1.18
- From an exclusive amount₹10,000.00 exclusive is ₹11,800.00 after tax
- × 1.18
Working GST out of an inclusive amount is not the same as taking the percentage off. Divide by 1 plus the rate; do not subtract the rate.
Most professional and business services sit at 18%. Rates vary by supply, and the correct rate is the one for the HSN or SAC code of what you are actually supplying.
GST is a cost only where you cannot recover it as input credit. A registered business buying a registered service is usually indifferent to it; an unregistered buyer is not.
The reverse calculation is where manual GST arithmetic goes wrong. Extracting 18% from an inclusive amount means dividing by 1.18, not subtracting 18% — those give different answers, and the difference grows with the amount.
Intra-state supplies split into central and state GST at half the rate each; inter-state supplies carry a single IGST at the full rate.
Frequently asked questions
- How do I remove GST from an amount?
- Divide by one plus the rate. To take 18% out of ₹11,800, divide by 1.18 to get ₹10,000 — subtracting 18% would give ₹9,676, which is wrong.
- What is the difference between CGST, SGST and IGST?
- An intra-state supply carries central GST and state GST at half the rate each. An inter-state supply carries a single integrated GST at the full rate, apportioned to the destination state afterwards.
- What is the GST rate on professional services?
- 18% for most professional and business services. The correct rate always follows the HSN or SAC code of what is actually being supplied, so check it rather than assuming.
About this tool
Built by the ViniOffice team. Figures and rules last reviewed 22 September 2026 against the statutory reference this team maintains. Indian statutory rates are date-effective and change by notification — confirm against the current one before running payroll or filing.
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