Percent Change Calculator
Find the percent increase or decrease from an old value to a new one.
Percent change
Old value first, new value second.
Change
+50%
Increase
Direction
25
Difference
1.5
New divided by old
Private: Everything runs in this page. Nothing you type is sent anywhere or saved.
On this page
Percent change examples
| Old to new | Change |
|---|---|
| 50 to 75 | +50% |
| 80 to 60 | -25% |
| 200 to 250 | +25% |
| 1 to 3 | +200% |
| 100 to 100 | 0% |
Formula
change = (new - old) / |old| x 100
How the percent change works
- Step oneType the old value in the first box.
- Step twoType the new value in the second box.
- Step threeRead the change: a plus sign means an increase, a minus sign a decrease.
What this tool does not do
- The starting value cannot be 0, because a change from zero has no percentage.
- For a negative starting value the percent is worked out on its size, so read it with care.
- It does not say whether a change is meaningful.
Frequently asked questions
Why is going up 50% and then down 50% not back to the start?
The second change is measured against a bigger number. 100 up 50% is 150, and 150 down 50% is 75.
What if the old value is zero?
A change from zero has no percentage, so the tool asks for a different old value.
How are negative numbers treated?
The change is divided by the size (absolute value) of the old number, so a move from -50 to -25 counts as an increase of 50%.