How to Calculate Percentage Increase and Decrease

Percentage change shows how much a value moved relative to its original amount. It is useful for prices, traffic, sales, budgets, metrics, and year-over-year comparisons.

The Formula

Subtract the original value from the new value, divide the result by the original value, and multiply by 100. A positive result means an increase. A negative result means a decrease.

Worked Example

If a value rises from 80 to 100, the difference is 20. Divide 20 by 80 to get 0.25, then multiply by 100. The percentage increase is 25%.

Decrease Example

If a value drops from 200 to 150, the difference is -50. Divide -50 by 200 to get -0.25, then multiply by 100. The percentage change is -25%, which means a 25% decrease.

Fastest Option

Use the Percentage Calculator if you want to skip manual steps. It helps with percentage share, percentage change, and related quick calculations.

FAQ

What value do I divide by?

Divide by the original value, not by the new value. The original value is the reference point for percentage change.

How do I know whether it is an increase or decrease?

If the new value is larger than the original value, it is an increase. If it is smaller, it is a decrease.

Where can I calculate percentage change quickly?

The Percentage Calculator handles the math directly and is useful for repeated comparisons.