See the amount before tax, the tax and the total
The GST Splitter is a simple arithmetic tool for exploring a percentage-based tax calculation. Enter an amount, supply a GST rate and choose whether the amount already includes tax. The result separates the starting value, the GST amount and the final total. You can also display the tax as one IGST amount or split it into CGST and SGST components. No purchase, account or spreadsheet is needed.
The tool does not choose a tax rate for a product or decide how a transaction should be treated. The initial 18% is an editable example, not a recommendation or a statement about the correct rate for your situation. Confirm your inputs using the information that applies to your transaction before using a result elsewhere.
How to use the calculator
- Enter the amount in rupees. Use up to two decimal places.
- Enter the percentage rate you want to calculate.
- Choose Add GST if your amount is before tax, or Remove GST if it already includes tax.
- Choose an equal CGST and SGST split or a single IGST breakdown.
- Select Calculate to update the results. Reset returns to the example values.
The calculator accepts non-negative amounts up to one billion rupees and percentage rates from zero to one hundred. These input limits describe what the tool can calculate; they do not describe permitted or applicable tax rates. If you change a value, the old results are hidden until you calculate again, helping you avoid reading an earlier answer as the current one.
Adding a percentage to a base amount
When the amount excludes tax, multiply it by the rate and divide by one hundred to find the tax. Then add that tax to the base. For example, a base amount of ₹1,000 with an example rate of 18% gives ₹180 in tax and a total of ₹1,180. Changing the rate changes the arithmetic immediately when you select Calculate.
Tax = base × rate ÷ 100. The final amount is the base plus the rounded tax. A zero-percent input leaves the final amount equal to the base. An amount of zero produces zero for each monetary result, whatever rate you enter.
Removing tax from an inclusive amount
To recover the base from a tax-inclusive amount, divide the inclusive amount by one plus the rate divided by one hundred. Subtract the recovered base from the inclusive amount to find the tax component. For ₹1,180 inclusive of an example 18% tax, the recovered base is ₹1,000 and the tax is ₹180.
Simply subtracting 18% of ₹1,180 would give a different answer because that percentage would be applied to the total rather than the original base. The Remove GST setting handles this distinction for you. Check that the amount on your source document is inclusive before choosing this setting.
Understanding the split and rounding
The equal-split view divides the calculated tax between two displayed components. The single-amount view shows the same tax as IGST. Switching the breakdown does not change the base or final total. It only changes how the tax amount is presented.
Amounts are rounded to two decimal places. Where the total tax cannot be divided into two identical whole-paise amounts, the second component absorbs the rounding difference so the displayed parts add back to the displayed tax. This simplified single-amount calculation does not reproduce line-by-line invoice rounding, discounts, extra charges, cess or other adjustments.
Frequently asked questions
Does the calculator identify the right rate?
No. You enter the rate. The page is a mathematical helper and does not classify goods, services or transactions.
Can I use it for an inclusive price?
Yes. Select Remove GST and enter the full inclusive amount. The tool then separates the base from the included tax.
Are my calculations uploaded?
The calculation runs in your browser. This tool does not upload or save the amounts you enter.
Does this generate a tax invoice?
No. It displays a calculation only. It does not create invoice records, verify a registration number or submit a return.