📈 Percentage Change Calculator
Calculate percentage increase or decrease between two values. See the change direction and amount.
About the Percentage Change Calculator
This percentage change calculator runs entirely in your browser. Enter an original value and a new value, then click Calculate to see the percentage increase or decrease instantly. Nothing is uploaded — all math happens on your device.
How percentage change is calculated
The percentage change is the difference between the new and original values, divided by the original value, multiplied by 100.
change = new − original
percentage change = (change / original) × 100
If the result is positive, the value increased. If negative, it decreased. A green arrow ↑ marks an increase, a red arrow ↓ marks a decrease.
How to use the calculator
- Enter the Original value (the starting number).
- Enter the New value (the ending number).
- Click Calculate to see the change amount, percentage change, and direction.
- Click Clear to reset.
Frequently asked questions
What's the difference between percentage change and percentage difference? Percentage change measures the change from an original value to a new one. Percentage difference compares two values without a clear "before" — it uses the average of the two as the base.
What happens if the original value is 0? A percentage change from 0 is undefined (division by zero). The calculator will warn you if the original value is 0.
Can I use negative numbers? Yes. The calculator handles negative original or new values, though the percentage change interpretation may be less meaningful.
Does this tool save my data? No. All calculations happen locally in your browser. Your inputs never leave your device.