GST Calculator India
Free GST calculator with CGST/SGST/IGST split and PDF download
Enter the amount before GST.
GST added
- Base amount
- ₹ 10,000.00
- CGST (9%)
- ₹ 900.00
- SGST (9%)
- ₹ 900.00
- Total GST
- ₹ 1,800.00
- Total payable
- ₹ 11,800.00
Need a full invoice with HSN, line items and totals in words? Use the GST Invoice Generator.
How GST is calculated in India
Add GST (exclusive)
When the price you have is before GST, add tax on top.
GST = Base × Rate%
Total = Base + GST
Remove GST (reverse)
When the price you have already includes GST, extract it.
Base = Total ÷ (1 + Rate/100)
GST = Total − Base
Intra-state (CGST + SGST)
When seller and buyer are in the same state, GST splits 50/50 between CGST (Centre) and SGST (State).
Inter-state (IGST)
When seller and buyer are in different states, the full GST is charged as a single IGST line.
Frequently asked questions
How is GST calculated in India?
GST = (Base amount × GST rate) / 100. For GST-exclusive prices, add this tax to the base. For GST-inclusive prices (reverse GST), the base = total / (1 + rate/100), and the tax is the difference.
What's the difference between CGST, SGST and IGST?
For intra-state sales (seller and buyer in the same state), GST splits 50/50 into CGST (Centre) and SGST (State). For inter-state sales, the full GST is charged as IGST (Integrated GST).
What are the GST slabs in India?
India has 5 main GST slabs: 0%, 5%, 12%, 18% and 28%. A 3% slab applies to gold and a 0.25% slab to rough diamonds. Most services fall under 18%.
How do I calculate reverse GST (extract GST from a total)?
Use the GST-inclusive mode in this calculator. Formula: Base = Total ÷ (1 + GST%/100). Example: ₹1,180 inclusive of 18% GST → Base = 1180 ÷ 1.18 = ₹1,000, GST = ₹180.
Is this GST calculator free to use?
Yes — 100% free, no signup, no email gate. You can also download a PDF of your calculation instantly.
Can I use this calculator for invoices?
Yes. For full GST-compliant invoices with HSN codes and totals in words, use our free GST Invoice Generator at /tools/gst-invoice-generator.
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