Add GST to any amount or remove GST from a GST-inclusive price. Pick from the 0, 5, 12, 18 and 28% slabs or enter a custom rate, choose CGST+SGST or IGST, and apply an optional discount before GST — with live results in Indian ₹ formatting.
The GST Calculator is a free online tool that helps you calculate Goods and Services Tax (GST) for any amount in seconds. Whether you are billing a customer, checking a supplier invoice, or verifying a GST-inclusive price, you can add GST to a net amount or remove GST from an inclusive amount and instantly see the tax breakdown — including the CGST, SGST or IGST split used in Indian GST returns.
GST = Taxable amount × (GST rate ÷ 100)
Total = Taxable amount + GST
When a discount is applied, Taxable amount = Base amount − Discount, and GST is calculated on this reduced value. For CGST+SGST, each component is half of GST; for IGST, the full GST is a single component.
Original (taxable) = Inclusive amount ÷ (1 + GST rate ÷ 100)
GST = Inclusive amount − Original
When a discount is applied in Remove GST mode, the discount is first deducted from the inclusive amount, then GST is extracted from the remainder using the formula above.
India uses a multi-rate GST structure. The most common slabs are 0%, 5%, 12%, 18% and 28%, with special rates for certain goods. This calculator supports all the standard slabs plus any custom rate you need, so you can handle gold (3%), precious stones, or any other special-case rate with ease.
If the supplier and the buyer are located in the same state, the GST is split equally into Central GST (CGST) and State GST (SGST). If the supply is interstate, the entire GST is charged as Integrated GST (IGST). Choosing the correct tax type matters for accurate invoicing and GST return filing, and this calculator shows the split automatically.
To add GST, multiply the taxable amount by the GST rate divided by 100. For example, ₹1,000 at 18% GST gives GST of ₹180 and a total of ₹1,180. In intrastate supplies this ₹180 is split equally into CGST ₹90 and SGST ₹90; in interstate supplies it is charged as IGST ₹180.
Divide the inclusive amount by (1 + GST rate ÷ 100) to get the original taxable amount, then subtract it from the inclusive amount to get the GST. For example, ₹1,180 inclusive at 18% gives an original amount of ₹1,000 and GST of ₹180.
When the supplier and buyer are in the same state, GST is split equally as CGST and SGST. When the supply is interstate, the full GST is charged as a single IGST component.
In this calculator the discount is always applied before GST. The GST is calculated on the amount after the discount has been deducted, which is the standard Indian GST treatment for discounts given at the time of supply.
Yes. The SUPRAVAT.IN GST Calculator is completely free, runs entirely in your browser, and does not require any sign-up or internet connection to calculate.