Percentage Change Calculator
Calculate increase or decrease instantly
Increase
0%
Difference: 0
Calculation Breakdown
((New – Old) / Old) × 100
Frequently Asked Questions
How do I calculate percentage change?
Subtract the old value from the new value. Divide that result by the old value. Finally, multiply by 100. If the result is positive, it’s an increase. If negative, it’s a decrease.
Why is the result undefined or infinity?
Percentage change cannot be calculated if the “Old Value” is zero. Mathematically, dividing by zero is undefined. If you started with 0 and now have 10, the increase is technically absolute, not a percentage.
Does this tool handle negative numbers?
Yes. It correctly calculates percentage changes even if your values are negative (e.g., a temperature drop from -5 to -10).