Percentage Decrease Calculator

The Percentage Decrease Calculator helps you determine exactly how much a value has dropped in percentage terms relative to its starting point. Whether you are tracking a product price discount, a reduction in exam scores, a fall in website traffic, a decline in stock value, or a drop in body weight, this calculator gives you the precise percentage decrease alongside the raw numeric reduction. Simply enter the original value and the new lower value — both results appear instantly. Expressing a reduction as a percentage rather than a raw number makes it easier to compare drops across different scales and communicate the magnitude of a change in a standardised way. A 15-unit drop from 100 and a 1,500-unit drop from 10,000 are both 15% decreases — the percentage immediately conveys the proportional significance of the reduction regardless of the absolute numbers involved, making it the clearest way to report declines in business metrics, scientific measurements, and everyday financial tracking.

Percentage decrease is calculated using the formula: (original − new) ÷ original × 100. The calculator first subtracts the new (lower) value from the original to find the amount of decrease. It then divides that decrease by the original value to express it as a proportion of the starting point, and multiplies by 100 to convert it to a percentage. The raw decrease amount is also shown alongside the percentage for full context. If the new value turns out to be greater than the original, the formula produces a negative result, which represents an increase rather than a decrease — in that case, the Percentage Increase Calculator is the more appropriate tool for clearer labelling and context.