How to calculate a percentage decrease

The formula

To decrease a value by a given percentage, apply: base value multiplied by (1 - rate / 100). This gives the final result directly. For à 20% decrease, the multiplier is 0.80.

Practical example

An item is priced at 300 EUR with à 20% discount. The calculation is: 300 x (1 - 20 / 100) = 300 x 0.80 = 240 EUR. The discount amount is 60 EUR. That is exactly what you will pay at checkout.

Where this calculation appears

Sales and promotional discounts are the most obvious example: applying à 30% reduction to a listed price. In accounting, businesses use this formula for straight-line depreciation of an asset, for instance a machine that loses 10% of its value each year. Investors also rely on it to model the depreciation of property or vehicles, estimating residual value after several years of use.