How this calculator works
The same GST rate can be added to a pre-tax price or extracted from a final price that already includes tax.
- Step 1Start with the price₹10,000before GST in the default example
- Step 2Apply the entered rate18%the rate you specify, not a rate lookup
- Step 3Show tax and total₹11,800including ₹1,800 GST
With GST extra, tax is the taxable price multiplied by the rate. With GST included, divide the total by one plus the rate to recover the taxable value.
What this estimate leaves out
- Rate and classificationThe tool does not identify goods, services, exemptions or applicable rates.
- Place of supplyThe intra-state or inter-state selector is an illustration, not a legal decision.
- Other tax detailsCess, credits, reverse charge, invoice rules and compliance are not calculated.
Worked example
- GST extra
tax = price × rate ÷ 100- Price including GST
total = price + tax- GST included
taxable value = total ÷ (1 + rate ÷ 100)
- Aamount before GST ₹10,000
- ruser-entered rate 18%
- GST amount₹10,000 × 18% ÷ 100₹1,800
- CGST componentGST ÷ 2 for this intra-state illustration₹900
- SGST componentGST ÷ 2 for this intra-state illustration₹900
- Total including GST₹10,000 + ₹1,800₹11,800
The calculator keeps full precision until display. Actual invoices may use rounding rules, classifications or tax components that are not represented here.
Reading your result
- GST extra₹11,800₹10,000 taxable value plus ₹1,800 GST.
- GST included₹8,475₹10,000 total contains ₹1,525 GST.
- CGST component
- SGST component
- IGST component
Which rate applies?
This calculator never chooses a GST rate. You enter it, because the rate depends on what is sold, and rates change.
GST rates are set by government notification for each class of goods or service, and they are revised from time to time. Check the current rate notification for your item, for example on the CBIC website, before you rely on a figure.
Before paying a supplier, the GSTIN validator checks that the number on the invoice has a valid format and check digit. To set a selling price before tax, use the margin and markup calculator or the discount calculator.
Common mistakes
Mistake: Entering a final price as if GST were extra.
Instead: Choose GST included when the entered amount is already the total.
Mistake: Assuming a commonly used rate applies to every item.
Instead: Verify the rate and classification for the specific goods or service.
Mistake: Treating the supply selector as a place-of-supply test.
Instead: Confirm the applicable treatment from current official guidance.
Mistake: Assuming the displayed amount is a tax invoice calculation.
Instead: Check applicable rounding and invoice rules separately.
This calculator performs arithmetic only. It does not determine tax liability or replace advice from a qualified tax professional.
Checking the method
A separate script recomputes every test case with exact fractions, and finds inclusive prices a second way by searching for the taxable value.
Read how we test our calculators, or browse more money calculators.