Percent Change
The calculator shows by how many percent a value increased or decreased and what change is needed to get back to the original value.
The percent change calculator shows by how many percent a value has increased or decreased: a price, a salary, an exchange rate, a follower count. It also tells you what change is needed to get back to the original value.
Percent change formula
Change = New − Old/Old · 100%
A positive result means an increase, a negative one means a decrease.
Example 1. A price went up from $80 to $100.
100 − 80/80 · 100% = 20/80 · 100% = +25%
Example 2. A price went down from $100 to $80.
80 − 100/100 · 100% = −20%
Why increases and decreases are not symmetric
In both examples the difference is the same $20, but in percent it is +25% and −20%. Percentages are always taken from the old value, and it differs in the two cases. That is why after a 50% drop you need a 100% rise to get back to where you started.
| Drop | Rise needed to recover |
|---|---|
| −10% | +11.11% |
| −20% | +25% |
| −50% | +100% |
| −75% | +300% |
Percent vs percentage points
If a rate goes from 10% to 12%, it rose by 2 percentage points, but by 20% relative to its previous value. For quantities that are already percentages, changes are usually given in percentage points.