Percentage Change Calculator
Enter an old value and a new value to get the percentage change between them — the tool handles both increases and decreases.
From old value to new value
Percentage increase
+25%
Difference
30
The percentage change formula
Percentage change = (new − old) ÷ old × 100. A positive result is an increase; a negative result is a decrease.
Example: going from 120 to 150 is (30 ÷ 120) × 100 = +25%. Going from 150 to 120 is (−30 ÷ 150) × 100 = −20%.
Why the up and down percentages differ
The same absolute change gives different percentages depending on the starting point, because the old value is the base. That is why a 25% rise and a 20% fall can cancel out to the same two numbers.
Frequently asked questions
How do I calculate percentage change?
Subtract the old value from the new value, divide by the old value, then multiply by 100. A positive answer is an increase and a negative answer is a decrease.