GST Calculator
Add GST to a net amount or remove it from a tax-inclusive price, with the CGST, SGST and IGST breakdown. Runs entirely in your browser.
Total including GST
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Enter an amount.
For the invoice
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All Calculators tools →This tool runs entirely in your browser. Nothing you enter is sent to our servers, so there is nothing for us to store or see.
About the GST Calculator
Add GST to a price, or work backwards from a tax-inclusive total to find the amount before tax and how much of it was tax. The breakdown into CGST, SGST and IGST is shown for putting on an invoice.
Removing GST is not the same as subtracting the percentage, and this is the mistake the tool exists to prevent. On an inclusive price of ₹118 at 18%, the tax is ₹18 and the net is ₹100 — because the tax was worked out on 100, not on 118. Subtracting 18% of 118 gives ₹21.24 and a net of ₹96.76, which is wrong by more than three rupees on a hundred-rupee item and by a great deal more on an invoice.
Within a state, GST is levied half by the centre and half by the state, so an 18% rate appears on the invoice as 9% CGST plus 9% SGST. Across states it is a single integrated levy, IGST, at the full 18%. The total is identical either way — the split is what the invoice has to show, and the switch is here because a tool cannot know where a transaction happened.
Rounding follows the amounts as written rather than as stored. A half at the second decimal place rounds up, which is what a ledger expects and what a naive floating-point round gets wrong about half the time.
How to use the GST Calculator
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Choose the direction
Add GST when you have a price before tax. Remove GST when the price you have already includes it — a shelf price, or a total on a receipt.
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Enter the amount and rate
Pick a standard slab or type any rate. Thousands separators are fine, including the Indian 1,00,000 grouping.
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Say whether it is within a state
Within a state the tax shows as CGST plus SGST, each half the rate. Across states it shows as a single IGST line at the full rate.
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Read the breakdown
The amount before tax, the tax and the total appear together, with the invoice split beneath.
Frequently asked questions
How do I remove GST from an inclusive price?
Divide by one plus the rate — for 18%, divide by 1.18. Do not subtract 18%. On a price of 118 the correct tax is 18, giving a net of 100; subtracting 18% would give 21.24 and a net of 96.76. The error grows with the rate and is a common cause of invoice disputes.
What is the difference between CGST, SGST and IGST?
For a sale within a state the tax is split equally between the central government (CGST) and the state government (SGST), so 18% appears as 9% plus 9%. For a sale between states it is charged as a single integrated tax, IGST, at the full 18%. The amount the customer pays is the same; only the split on the invoice differs.
Which GST rate applies to my product?
That depends on the HSN or SAC code for the item, and the slabs are 0, 0.25, 3, 5, 12, 18 and 28 per cent, with cess on some categories. This tool does the arithmetic for whatever rate you give it; it does not classify goods, because that requires the code and the current notification.
Does this work for VAT or sales tax?
Yes for VAT and for any tax charged as a straight percentage — the add and remove arithmetic is identical, and you can type any rate. It does not fit US-style sales tax that varies by county and is never included in the displayed price, and it does not handle cess or compounded taxes.
Are my figures sent anywhere?
No. Everything is calculated in your browser and nothing is transmitted or stored, so invoice values, order totals and margins stay on your device.