GST Calculator
Add GST to a base amount or extract GST from a tax-inclusive total.
Add or remove GST
Use any manually chosen GST rate to separate the taxable value, tax amount and final total.
How to use it
- Choose whether your amount excludes or includes GST.
- Enter the amount and GST rate.
- Choose the preferred tax split display.
- Select Calculate GST.
Formula
Exclusive GST = base amount × rate ÷ 100
Inclusive base = total ÷ (1 + rate ÷ 100)
Worked example
Assumptions and limitations
Informational estimate only. The calculator does not determine which rate applies to a product, service or transaction. Confirm classifications, exemptions, place-of-supply rules and current rates using official guidance or a tax professional.
How to Remove GST from an Inclusive Amount
Divide the GST-inclusive total by one plus the GST rate expressed as a decimal. Then subtract the amount excluding GST from the inclusive amount to find the GST removed.
Amount excluding GST = Inclusive amount ÷ (1 + GST rate ÷ 100)
GST removed = Inclusive amount − Amount excluding GST
Worked example: remove GST
₹1,180 ÷ 1.18 = ₹1,000 before GST.
GST removed = ₹180.
Frequently asked questions
How do I remove GST from an inclusive amount?
Divide the inclusive amount by one plus the GST rate expressed as a decimal.
Does this calculator choose the correct GST rate?
No. You must enter or select a rate appropriate to your transaction.
What is the difference between CGST, SGST and IGST?
For this estimate, CGST and SGST divide the tax equally, while IGST displays the full tax as one amount.