๐ท๏ธ Discount Calculator
Calculate the final price from an original price and discount rate, or reverse-calculate the discount rate or original price.
What Is a Discount?
A discount is a reduction from the original price, usually quoted as a percentage off. A 30% discount means you pay 70% of the list price: 30% of 50 is 15, so the final price is 35. The saving grows with the price, and discounts never stack the way they look โ two successive 30% cuts remove 51% in total, not 60%.
Formula
Discounted Price = Original Price ร (1 โ Rate / 100)
Discount Rate = (1 โ Discounted / Original) ร 100
Reverse mode is useful for verifying original prices from sale advertisements.
The second and third modes solve the same relationship for a different unknown, which is how you check a "was 50, now 35" claim against the advertised rate.
Worked Examples
30% off 50 โ 50 ร (1 โ 30/100) = 35
Backwards: a price cut from 50 to 35 โ (1 โ 35/50) ร 100 = 30% off
Watch Out For
A percentage "off the list price" can be measured against an inflated list price, and shops sometimes raise prices just before a sale. Stacked discounts apply to the price that is already reduced, so an extra 20% off sale items is not 50% off when the sale itself was 30%. Sales tax is added after the discount, never before.
Frequently Asked Questions
- How do I calculate a 30% discount?
- Multiply the original price by 0.7, or subtract 30% of it: 50 ร 0.7 = 35, so you pay 35 and save 15.
- How do I work out the discount rate from two prices?
- Divide the sale price by the original price and subtract the result from 1: 35 รท 50 = 0.7, so the discount is 30%.
- Is "50% off plus an extra 20%" the same as 70% off?
- No. The second discount applies to the price that is already reduced: 100 โ 50 โ 40, which is 60% off in total, not 70%.