A percentage change calculator computes how much a value has increased or decreased as a percentage of the original value. It is used to compare prices, statistics, measurements and any other values where you want to express the change relative to the starting point.

1. Enter the original (old) value.
2. Enter the new value.
3. Click Calculate to see the percentage change.

Old: 80, New: 100 → Change: +20 → Percentage increase: 25%
Old: 100, New: 80 → Change: −20 → Percentage decrease: −20%

Note that a 25% increase followed by a 20% decrease does not return to the original value — percentage changes are not symmetric. An increase from 80 to 100 is 25%, but a decrease from 100 to 80 is only 20%.

• Confusing percentage change with percentage point change — if a rate goes from 5% to 8%, the percentage change is 60%, but the percentage point change is 3.
• Using the new value as the denominator instead of the old value.

What is the difference between percentage change and percentage point change?

Percentage change is relative to the original value. Percentage point change is the absolute arithmetic difference. If interest rates rise from 2% to 5%, that is a 3 percentage point increase but a 150% percentage change.

Can the original value be negative?

The formula works with negative values, but the result can be counterintuitive. For example, a change from −10 to −5 is a 50% increase (the value became less negative).