Discount Calculator

How it is calculated

The tool takes a price before discount and a percentage and works out three figures: discount amount = original × rate / 100, final price = original − discount amount and the saving, which equals the discount amount. The rate is a percentage, so 25 means 25%, not 0.25.

The original price must be zero or more. A negative rate is not rejected and works like a markup, raising the price. It applies one discount to the whole price: for two successive discounts (for example 20% then 10%) run the tool twice, using the first result as the new original price. They do not add up to 30%. Tax is not included.

Common mistakes

• Adding two discounts together. 20% plus 10% off is not 30% off: after the first cut you take 10% off the lower price, which gives 28% in total.
• Entering the sale price as the original price, which shows the saving on the wrong base.
• Typing 0.25 instead of 25 for the rate, producing a 0.25% discount.
• Forgetting that VAT or sales tax may be added after the discount, so the checkout total can differ.