Free GST Calculator
Add GST to a price or extract it from a GST-inclusive amount — no signup, nothing sent to a server.
Original amount
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GST amount
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CGST + SGST
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Total amount
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How to use the GST calculator
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1
Choose Add or Remove GST
Pick "Add GST" if you have a base price, or "Remove GST" if you have a GST-inclusive amount.
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2
Enter the amount
Type the amount you're working from.
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3
Pick a GST rate
Choose a standard slab (5%, 12%, 18%, 28%) or enter a custom rate.
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4
Read the breakdown
Original amount, GST amount, CGST/SGST split, and total all update instantly.
Example use cases
Quoting prices to clients
Work out what a GST-inclusive price should be for a given base rate.
Checking a supplier invoice
Verify that the GST charged on a bill matches the stated rate.
Reverse-calculating from a receipt
Extract the base amount and tax paid from a GST-inclusive total.
Frequently asked questions
How do I add GST to a price?
GST amount = original amount × (rate ÷ 100). Total = original amount + GST amount. For example, ₹1,000 at 18% GST adds ₹180, for a total of ₹1,180.
How do I remove GST from an inclusive amount?
Original amount = inclusive amount ÷ (1 + rate ÷ 100). For example, ₹1,180 inclusive of 18% GST works back to ₹1,000 base plus ₹180 GST.
What is the CGST/SGST split shown here?
For intra-state supplies, GST is typically split equally into Central GST (CGST) and State GST (SGST), each being half the total GST rate. For inter-state supplies, the full amount is charged as IGST instead.
Is my amount sent to a server?
No. The calculation runs entirely in your browser — nothing is transmitted or logged.