GST Calculator
Work out GST exclusive (add GST to a base price) or GST inclusive (extract the base price from a GST-included total), with the CGST/SGST split shown.
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Total amount
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- Base amount
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- GST amount
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- CGST
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- SGST
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Enter an amount and GST rate above to see the breakdown.
This tool performs the mathematical GST split only. It does not determine whether GST applies to a given good or service, which HSN/SAC code it falls under, or which rate is correct for your situation — check that against current tax rules or a professional.
Every calculation runs in your browser. Nothing you enter is uploaded to a server.
How GST is calculated
GST exclusive — the price you entered does not yet include GST:
GST = base price × rate ÷ 100
total = base price + GST
GST inclusive — the price you entered already includes GST, and this works backward to find the base:
base = total price ÷ (1 + rate ÷ 100)
GST = total price − base
CGST and SGST are shown as an even split of the total GST amount, which is how intra-state GST is structured in India; an inter-state transaction instead charges the full amount as IGST with no split — this tool always shows the CGST/SGST view.
Exclusive or inclusive — which do I have?
If the number you're starting from is what a supplier quoted before tax, that's exclusive. If it's the final amount on a receipt or invoice, that's inclusive — GST is already folded in, and this tool works backward from it rather than adding tax on top a second time.
Frequently asked questions
What is the difference between GST exclusive and inclusive?
Exclusive means the price you have doesn't include GST yet, so GST is added on top. Inclusive means GST is already baked into the price, and the tool works backward to find the base amount.
Why does the inclusive calculation not just subtract the GST percentage from the total?
Because the percentage applies to the base price, not the total. Subtracting 18% of the total price would over-correct — the correct base is total ÷ (1 + rate ÷ 100), which the tool does for you.
What are CGST and SGST?
For a transaction within the same state in India, GST is split evenly into Central GST and State GST. An inter-state transaction instead charges the whole amount as IGST with no split — this tool always shows the CGST/SGST view.
Does this tool tell me whether GST applies to my situation?
No — it performs the mathematical split only. Whether GST applies, which rate is correct, and which HSN/SAC code fits your good or service are separate questions that depend on current tax rules.
Which GST rate should I use?
5%, 12%, 18% and 28% are the common slabs and are offered as quick picks, but you can type any rate — the calculation works the same way regardless of the number.