What is the GST Calculator?
Goods and Services Tax (GST) is India's unified indirect tax, levied at 0.25%, 3%, 5%, 12%, 18%, or 28% depending on the goods or services supplied. Businesses need to add GST when invoicing, while consumers often want to extract the tax from an MRP that already includes it.
For intra-state supplies, GST is split equally between Central GST (CGST) and State GST (SGST). For inter-state supplies, the whole amount is charged as Integrated GST (IGST). This calculator handles both directions — GST-exclusive (add tax) and GST-inclusive (remove tax) — and shows the CGST/SGST split automatically.
GST Calculator Formula & How It Works
- Base = Price before GST
- Price = GST-inclusive amount
- r = GST rate (%)
- CGST = SGST = GST ÷ 2 (intra-state)
To add GST, multiply the base price by the rate. To remove GST from an inclusive price, divide by (1 + rate/100) — do not simply subtract the percentage, as that overstates the tax. For example, ₹118 at 18% contains ₹18 of GST (118 ÷ 1.18 = 100), not ₹21.24.
Worked Examples
Add 18% GST to ₹10,000
GST = ₹1,800 (CGST ₹900 + SGST ₹900). Invoice total = ₹11,800.
Remove 28% GST from ₹64,000 (inclusive)
Base price = ₹50,000 and GST = ₹14,000 (CGST ₹7,000 + SGST ₹7,000).