GST basics
GST on a discounted price: calculate the total with an example
See how a simple discount changes the taxable value, GST amount, and final price when tax is added separately.
Updated July 30, 2026 · 4 min read
Work out the discounted price first
In a simple tax-added example, start with the listed base price and reduce it by the discount. A Rs. 1,000 item with a 10% discount has a discounted base price of Rs. 900.
This example assumes the discount is applied to the taxable base and a single GST rate is then added. An invoice, offer, or specific transaction can have other terms, so treat the result as a quick illustration.
Apply the GST rate to the reduced base
If 18% GST is added to the Rs. 900 discounted base, the GST amount is Rs. 162. Add it to the discounted base to get a final total of Rs. 1,062.
The key point is that the GST amount in this illustration is calculated from Rs. 900, not the original Rs. 1,000. Enter the right rate and check whether the price you have is before or after tax.
Check the actual invoice and tax treatment
A general calculator cannot determine the correct GST rate, classification, place of supply, exempt status, or whether CGST, SGST, or IGST applies. A final invoice can also include other adjustments that this example does not cover.
Use the calculation to understand a price or compare an offer, then rely on the supplier's invoice and official GST information when you need a tax or business record.
Sources and further reading