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Percentage change calculator
Percent increase or decrease from an old value to a new one.
Quick answer
Enter the old and the new value. A rise from 80 to 100 is a 25% increase.
Read the guide: How to calculate percentage: every common case
Percentage increase
25.00%
- Difference
- 20.00
How it works
Percentage change compares the size of the move with where you started.
It is not symmetric: a 25% rise needs only a 20% fall to return to the start.
Use it for price rises, marks, population, salary hikes and anything measured at two points in time.
The formula
- Percentage change = (new โ old) รท |old| ร 100
- A positive result is an increase and a negative one is a decrease
A worked example
From 80 to 100: (100 โ 80) รท 80 ร 100 = 25%. From 100 back to 80 is (80 โ 100) รท 100 ร 100 = โ20%, so the way back is a smaller percentage.
Common questions
How do I calculate percent increase?
Subtract the old value from the new, divide by the old value and multiply by 100.
Why is a 50% rise then a 50% fall not back to the start?
The fall is worked out on the larger number. 100 up 50% is 150, and 150 down 50% is 75.
What if the old value is 0?
The percentage is undefined, so the calculator asks for a different starting value.
How is this different from percentage difference?
Percentage change has a clear before and after. Percentage difference compares two values with no order, using their average as the base.