Discount Calculator
The sale price and how much you save, including an extra coupon on top and any tax added at the till.
Updated · By Niraj Kumar
https://checkpre.com/everyday/discount-calculator
How the Discount Calculator works
Each discount comes off the price that is left after the one before it, so stacked discounts multiply rather than add. 20% off and then an extra 10% leaves 0.8 × 0.9 = 72% of the price, a 28% discount rather than 30%. Tax, when a shop adds it at the till, is charged on the discounted price.
price × (1 − d₁) × (1 − d₂)- d₁
- The main discount, as a decimal
- d₂
- An extra coupon or bank offer applied after it
- Total discount
- 1 − (1 − d₁)(1 − d₂)
Worked example
A ₹2,000 jacket at 20% off, with an extra 10% off at checkout.
- 1After 20% off: 2,000 × 0.8 = ₹1,600
- 2After the extra 10%: 1,600 × 0.9 = ₹1,440
- 3Saving: 2,000 − 1,440 = ₹560
- 4Total discount: 560 ÷ 2,000 = 28%
You pay ₹1,440 and save ₹560, a 28% discount rather than the 30% the two numbers suggest.
Frequently asked questions
Is 20% off plus 10% off the same as 30% off?
No, it is 28%. The second discount applies to the already reduced price, so it takes 10% of a smaller number. The gap grows with bigger discounts: 50% plus 50% is 75% off, not free.
How do I work out a discount in my head?
Find 10% by moving the decimal point one place, then scale. 10% of ₹2,000 is ₹200, so 20% is ₹400 and 25% is ₹500. For 30% off, take 3 × 10%.
How do I find the original price from a sale price?
Divide by what is left after the discount. A ₹1,200 price after 25% off was 1,200 ÷ 0.75 = ₹1,600. The percentage calculator can also do this in reverse.
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