GST Reverse Calculator
Find the taxable value from a known GST amount, or work out which GST rate was charged from before and after prices.
What is the GST Reverse Calculator?
Sometimes you know only the GST shown on a bill, or only the prices before and after tax. Reverse calculation recovers the missing figures.
How does it work?
Taxable value = GST amount × 100 ÷ rate. The rate charged = (total − value) ÷ value × 100.
Formula
Value = GST × 100 ÷ Rate
Rate = (Total − Value) ÷ Value × 100
Example
₹1,800 of GST at 18% means a taxable value of ₹10,000 and a total of ₹11,800.
Frequently asked questions
What are the current GST rates?
Since 22 September 2025, most goods and services fall under 5% or 18%, with 40% for luxury and sin goods. Special rates of 0.25% and 3% apply to precious stones and metals. The 12% and 28% slabs remain selectable for older invoices.
When is IGST charged instead of CGST + SGST?
IGST applies when the supplier and the place of supply are in different states (and on imports). For supplies within the same state, the rate is split equally into CGST and SGST (or UTGST in union territories).
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