Understanding your result
The taxable base and GST add to the inclusive total. In split mode, the total tax is divided equally between CGST and SGST; the rate you enter remains the combined rate. The presentation selector does not determine which treatment legally applies.
For reversing a percentage change that is not specifically GST, use the Reverse Percentage Calculator and choose whether the original amount was increased or reduced.
The formula
Reverse GST divides by the tax-inclusive multiplier. Subtracting the entered percentage directly from the total uses the wrong base. Calculations retain full precision and display amounts to currency precision; invoice-level rounding policies can create small differences.
Extracting GST from 1,180
At an illustrative total rate of 18%, an inclusive amount of 1,180 contains a base of 1,000 and GST of 180. An equal CGST and SGST presentation shows 90 in each component, not 180 in each.
How to use this calculator
- Enter the invoice amount and select whether it already includes GST.
- Enter the total rate applicable to the supply rather than relying on the illustrative default.
- Choose the tax presentation needed and inspect the base, tax, and total.
Rate selection is separate from arithmetic
GST treatment depends on the supply, classification, place-of-supply rules, exemptions, and other relevant requirements. This calculator applies the rate and presentation you provide. It does not classify goods or services, verify eligibility, or fetch current rate notifications.
For an invoice with several items at different rates, calculate each taxable line or same-rate group separately. A single blended rate may not preserve the item-level tax breakdown. Discounts, cess, freight treatment, reverse charge, and input tax credits can require additional handling outside this price calculation.
Assumptions & limitations
What this calculation assumes
- One entered rate applies to the full taxable base.
- Split presentation allocates the combined tax equally.
- Amounts are positive or zero and use one currency.
What to keep in mind
- No cess, tax credits, returns, exemptions, or compliance decisions are calculated.
- This is tax arithmetic using user-supplied assumptions, not a tax determination.
Common questions
Is the default rate always applicable?
No. It is a worked-example input. Confirm the rate for your specific supply before using the result.
Does reverse GST mean reverse charge?
No. Here it means extracting included tax from a gross price. Reverse-charge obligations are a separate legal concept and are not assessed by this calculator.