Percent Change Calculator
Enter an old value and a new value to see the percentage change between them, or apply a percentage increase or decrease to a number.
Result
- Direction
- 25% increase
- Difference
- 20
- New value as a multiple of the original
- 1.25 ×
- Percentage difference (relative to the average)
- 22.2222%
Formula
- Percent change = (new − old) ÷ |old| × 100
- Increase by p%: new = old × (1 + p ÷ 100)
- Decrease by p%: new = old × (1 − p ÷ 100)
- Percentage difference = |a − b| ÷ ((a + b) ÷ 2) × 100
How the Percent Change Calculator works
Percent change compares the difference between two values with the starting value. A positive result is an increase and a negative result is a decrease.
An increase followed by an equal decrease does not return to the start. Raising 80 by 25 percent gives 100, but lowering 100 by 25 percent gives 75, because the second percentage is taken of a larger number.
Percentage difference is a different measure, used when neither value is the starting point. It compares the gap with the average of the two.
Worked example
From 80 to 100: (100 − 80) ÷ 80 × 100 = 25 percent increase. From 100 back to 80: (80 − 100) ÷ 100 × 100 = −20, a 20 percent decrease.
Frequently asked questions
How do I calculate percent decrease?
Subtract the new value from the old, divide by the old value and multiply by 100. A price falling from 50 to 40 is a decrease of 10 ÷ 50 × 100 = 20 percent.
Can a percent increase be more than 100?
Yes. Doubling is a 100 percent increase and tripling is a 200 percent increase. A decrease cannot exceed 100 percent for positive quantities.
What is the difference between percent change and percentage points?
A rate going from 4 percent to 5 percent rises by 1 percentage point, which is a 25 percent change.
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Calculations run in your browser and nothing you enter is sent to a server. Results are provided for general information. Check critical figures independently before relying on them.