How Discounts and Sale Prices Are Calculated
Discounts are expressed as a percentage reduction from the original price. Understanding how to calculate discounts helps you quickly assess whether a sale is good value, compare offers across stores, and budget shopping trips. The key insight is that a X% discount multiplies the price by (1 - X/100).
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Formula
Discount Calculator
Find the final price after a percentage discount and how much you save.
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Worked Example
Given:
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FAQs
How do I calculate a discount mentally?
For common percentages: 10% = move the decimal one place left. 20% = double the 10% amount. 25% = divide by 4. 50% = divide by 2. For example, 25% off $80: $80 ÷ 4 = $20 discount, final price = $60.
How do stacked discounts work?
Stacked discounts are applied sequentially, not added. A 20% discount followed by an extra 10% off is not 30% off. It is: 1 - (0.80 × 0.90) = 28% total discount. Always apply each discount to the current price, not the original.
How do I find the original price from a sale price?
Divide the sale price by (1 - discount%). For example, if something costs $75 after a 25% discount: original price = $75 ÷ 0.75 = $100.