Free tool
GST Calculator
Add or remove GST from any amount. Pick the rate, intra-state or inter-state, and get the CGST/SGST or IGST split with the total.
- Base value
- ₹ 10,000.00
- CGST (9%)
- ₹ 900.00
- SGST (9%)
- ₹ 900.00
- Total GST
- ₹ 1,800.00
- Total payable
- ₹ 11,800.00
A worked example, end to end
Scenario
A seller in Bengaluru issues an invoice for ₹10,000 (net of GST) to a buyer in Mumbai. GST 18%.
Computation
- Supply type. Karnataka → Maharashtra = inter-state, so IGST.
- IGST. 18% × ₹10,000 = ₹1,800.
- Gross. ₹10,000 + ₹1,800 = ₹11,800.
- Reverse (extract). A gross of ₹11,800 inclusive at 18% gives net ₹11,800/1.18 = ₹10,000 and GST ₹1,800.
- Same state. If buyer were in Karnataka: CGST 9% (₹900) + SGST 9% (₹900). Same gross, different routing.
Free download
GST rate cheat sheet (PDF).
The 100 most-used HSN and SAC codes mapped to their GST rate. Industry-wise sections for IT services, restaurants, retail, e-commerce, exports and consulting. Print and stick on the finance team wall.
How GST is calculated
The Goods and Services Tax (GST) in India applies at five standard rates: 0%, 5%, 12%, 18% and 28%. The rate depends on the HSN classification of the goods or the SAC for services. Most B2B services are at 18%; most consumer staples are 5% or exempt; luxury and sin goods are at 28% (often with cess).
Intra-state supplies (same state for supplier and place of supply) attract two equal taxes: CGST (Central GST) and SGST (State GST). At 18% combined, that is 9% CGST + 9% SGST. Inter-state supplies attract a single IGST (Integrated GST) at the full rate.
To add GST to a base amount, multiply the rate (e.g. 18%) and add to the base. To remove GST from a tax-inclusive amount, divide by (1 + rate/100) to get the base, then subtract.
Examples
- Add 18% to ₹10,000: base ₹10,000 + GST ₹1,800 = ₹11,800 total. Intra-state: ₹900 CGST + ₹900 SGST. Inter-state: ₹1,800 IGST.
- Remove 18% from ₹11,800: base ₹10,000 + GST ₹1,800. The reverse calculation.
- Add 5% to ₹1,000: base ₹1,000 + GST ₹50 = ₹1,050. Common for restaurants and packaged food.
GST FAQ
Common questions.
How do I know which GST rate to apply?
GST rates are set by the GST Council and notified by CBIC. The rate depends on the HSN (for goods) or SAC (for services) code. Most professional and software services are at 18%; restaurants are at 5% (without ITC); luxury goods and sin goods are at 28% with cess. Look up the right HSN/SAC for your supply.
What is the difference between CGST, SGST and IGST?
CGST is collected by the centre, SGST by the state, IGST by the centre and shared with the destination state. Intra-state supplies (within one state) attract CGST + SGST in equal halves of the rate. Inter-state supplies (between states or with SEZ) attract IGST at the full rate.
Can I claim ITC on the GST paid?
Generally yes, if you are GST-registered and the input is used in the course or furtherance of business. ITC is claimed via GSTR-3B and reconciled against GSTR-2B. Some categories (motor vehicles for personal use, food, club memberships) are blocked from ITC.
Do exempt or zero-rated supplies appear in this calculator?
The 0% rate covers exempt supplies (where output GST is nil). Zero-rated supplies (exports, SEZ) are different: output is nil but ITC can be claimed. The calculator outputs zero GST at 0%; the distinction matters for ITC claims.
Where is this calculator most useful?
Quick reverse-calculation when a vendor sends a tax-inclusive quote. Pre-quoting work to a customer to show the GST split. Validating a third-party invoice against expected GST. For ongoing book-keeping and reconciliation across hundreds or thousands of invoices, OneFinOps automates this end-to-end.
Related tools
More GST tools.
- HSN & SAC Code FinderSearch 670+ HSN and SAC codes with GST rates.
- GST Invoice GeneratorGenerate a GST-compliant tax invoice with auto CGST/SGST/IGST split.
- GST Late Fee CalculatorLate filing fee + 18% Section 50 interest for delayed GSTR returns.
- E-Way Bill CalculatorCheck if an e-way bill is required and calculate its validity.
Run your GST on OneFinOps.
Direct GSTN integration, GSTR-2B reconciliation, e-invoicing native, multi-state filings, audit trail. The calculator is one moment; the platform handles the rest.