Discount Calculator
Work backwards
I paid this after a discount — what was it before?
Why stacked discounts are smaller than they look
"50% + 20% off" reads like 70%, and it is not. The extra 20 comes off what is left after the first cut, so the real total is 60%. The gap grows with the numbers: 50 plus 50 is not free, it is 75% off. This is the most common way a sale looks better than it is.
Where GST fits
Under Indian GST, tax applies to the discounted price when the discount appears on the invoice — so a discount reduces the tax as well. The breakdown above shows the tax figure separately, which is what to check a bill against.
Working backwards from what you paid
To find the original price, divide by one minus the discount. Adding the percentage back to what you paid always undershoots, because the percentage was taken on the larger number.
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Frequently Asked Questions
No, and shops rely on you thinking it is. The second discount comes off the already-reduced price, so 50 then 20 is 60% off in total, not 70. On a 2000 rupee item that is a 200 rupee difference.
No. Applying 30% then 10% gives exactly the same result as 10% then 30% — both multiply out to 0.63 of the original. Only the total matters, not the sequence.
After. Under Indian GST, tax is charged on the discounted price when the discount is shown on the invoice, so a discount genuinely reduces the tax you pay too. The tool shows both so you can check a bill.
Divide by one minus the discount, not add the percentage back. An item at 800 after 20% off was 1000 — adding 20% to 800 gives 960, which is wrong.
Twenty-five per cent off, if the second item is half price. A true BOGO where the second is free is 50% off — but only if you actually wanted two.