Divide the number by 100 (move the decimal place two places to the left).Multiply this new number by the percentage you want to take off.Subtract the number from step 2 from the original number. This is your percent off number.A percent off of a product or service is a common discount format. A percent off of a product means that the price of the product is reduced by that percent. For example, given a product that costs $279, 20% off of that product would mean subtracting 20% of the original price from the original price. For example:20% of $279 = 0.20 × 279 = $55.80
$279 - $55.80 = $223.20
You would therefore be saving $55.80 on the purchase for a final price of $223.20.
For this calculator, a "stackable additional discount" means getting a further percent off of a product after a discount is applied. Using the same example, assume that the 20% discount is a discount applied by the store to the product. If you have a coupon for another 15% off, the 15% off would then be applied to the discounted price of $223.20. It is not a total of 35% off of the original price. It is less:
15% of $223.20 = $33.48
$223.20 - $33.48 = $189.72
Thus, with a 20% discount off of $279, and an additional 15% off of that discounted price, you would end up saving a total of:
$55.80 + $33.48 = $89.28
This equates to a 32% discount, rather than a 35% discount, and this calculation is how the calculator is intended to be used. As an example, to more efficiently compute the discount described above:
Final price = (0.80 × 279) × 0.85 = $189.72
This is because 80% of the original price is the same as subtracting 20% of the original price from the original price. The same is true for 85% and 15% case applied to the discounted price.
