GST Calculator
Calculate GST instantly — add GST to a base price or remove GST from a GST-inclusive price. Shows CGST, SGST, and IGST split.
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How to use this calculator
- 1
Enter the amount — either the base price (if adding GST) or the total price (if removing GST).
- 2
Select the GST rate from your invoice or the CBIC rate notification. The tool does not map any item or service to a slab, and the drop-down labels are only broad hints.
- 3
Choose whether you're adding GST to a base price or extracting it from an inclusive price.
- 4
Select intra-state for same-state transactions (CGST + SGST) or inter-state (IGST).
Frequently asked questions
What does this tool calculate for adding GST?
In add mode this tool treats your amount as the base price, multiplies it by the chosen rate to get the GST, and adds the two to give the GST-inclusive total. At 18% on ₹1,000 it shows ₹180 of GST and a total of ₹1,180. The amount is not rounded until display, which is to two decimal places.
How does remove mode work?
In remove mode your amount is the GST-inclusive total. The tool divides it by one plus the rate to get the base price and subtracts to get the GST. For ₹10,500 at 5% it shows a base price of ₹10,000 and GST of ₹500. For ₹2,500 at 40% it shows ₹1,785.71 of base price and ₹714.29 of GST, because the division is exact and only the display is rounded.
Which rates are built into the tool?
This tool offers four fixed choices: 0% (nil or exempt), 5%, 18% and 40%. These are the figures built into this tool and reflect the structure in place since 22 September 2025: main rates of 5% and 18% plus a 40% special rate, with the earlier 12% and 28% slabs removed. A few items keep their own special rates, such as 0.25% or 3%, and some items (tobacco, for example) were handled separately; those are not in the drop-down. The tool does not provide an item-to-slab mapping and does not look up the rate for any item or service. GST rules change, the choices in this tool are not updated automatically, and the CBIC rate notifications, the GST Council or a chartered accountant decide which rate applies to a given supply, so choose the rate from your invoice or the official notification.
How does the intra-state versus inter-state choice change the output?
It changes only the split, not the total. Intra-state shows CGST and SGST as two equal halves of the GST, for example 9% and 9% at 18%. Inter-state shows the whole GST as IGST. The tool does not work out whether a transaction is intra-state or inter-state; you decide that from the place of supply.
Does the tool include cess, TCS, TDS or input tax credit?
No. It shows one rate applied to one amount. There is no compensation cess, no tax collected at source, no reverse charge, no composition scheme, and no input tax credit netting. It also does not handle a bill with several items at different rates; run each item separately and add the results.
What happens with a zero amount or a zero rate?
An amount of 0, which is also what a cleared box becomes, returns ₹0.00 in every line. The 0% choice returns the amount unchanged with no GST, and the CGST and SGST lines show ₹0.00 at 0%. Negative amounts are not blocked and would simply produce negative lines, so enter positive figures.
Why do CGST and SGST show decimal percentages?
The tool halves the chosen rate for each of the two components, so a 5% choice shows 2.5% each and a 40% choice shows 20% each. The label is just the rate divided by two. If your invoice shows different state and central components, the tool will not reflect that.
GST Calculator India — add or remove GST with a CGST/SGST/IGST split
Two modes, one rate
The calculator takes an amount, a rate from a fixed list of four choices, a mode, and a transaction type. Add mode treats the amount as the price before GST; remove mode treats it as the total with GST already included. The rate list is 0% (nil or exempt), 5%, 18% and 40%, the figures built into this tool for the structure in place since 22 September 2025, when the 12% and 28% slabs were removed. This page does not tell you which rate applies to a product or service: the item-to-slab mapping is not provided by the tool and sits in CBIC notifications, which also carry a few special rates such as 0.25% and 3%. GST rules and rates are revised from time to time and the tool’s list is not updated automatically, so use the rate shown on your invoice or the official notification, and ask a chartered accountant if unsure. The tool always works on exact values and rounds only for display.
GST on ₹1,000 at each built-in rate
The table shows the result of adding GST to a base price of ₹1,000 at each choice in the list, intra-state. The CGST and SGST columns are each half of the GST. This layout makes it easy to see that the totals step up in proportion to the rate and that the two components always sum to the whole.
| Rate | GST | CGST each | Total |
|---|---|---|---|
| 0% | ₹0.00 | ₹0.00 | ₹1,000.00 |
| 5% | ₹50.00 | ₹25.00 (2.5%) | ₹1,050.00 |
| 18% | ₹180.00 | ₹90.00 (9%) | ₹1,180.00 |
| 40% | ₹400.00 | ₹200.00 (20%) | ₹1,400.00 |
Worked example: extracting GST from an inclusive bill
Suppose a supplier quotes ₹10,500 including GST at the 5% choice. In remove mode the tool divides by 1.05, so the base price is ₹10,000.00 and the GST is ₹500.00; set to intra-state it shows ₹250.00 as CGST and ₹250.00 as SGST. Set to inter-state with an 18% rate and an inclusive total of ₹1,180, it returns a base price of ₹1,000.00 and one IGST line of ₹180.00. Dividing an inclusive total by 1.05 is not the same as subtracting 5% of it, and the tool does the correct division.
CGST, SGST and IGST in the output
The tool shows either two lines or one. With intra-state selected, the GST is split equally into CGST and SGST, and each line is labelled with half the rate. With inter-state selected, a single IGST line carries the full amount. The choice changes only the presentation, never the total. The tool does not decide the place of supply, so selecting the wrong transaction type produces a correct total with the wrong split.
What is not included
The calculator handles one amount at one rate. It does not add any cess, handle tax collected at source, reverse charge or composition schemes, or net off input tax credit. It cannot split a mixed invoice, round per line as an invoice might, or confirm that a rate applies to your goods or services. Use it to check arithmetic on a single line, then rely on the invoice and the tax authority for anything about which rate or treatment applies.
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Results are estimates for informational purposes only and do not constitute professional financial, medical, legal, or technical advice. Read full disclaimer →