Percentage Increase/Decrease Calculator
Find the percentage change between two numbers.
This tool runs entirely in your browser. Your files are never uploaded to a server.
20%
What this calculator does
Calculates percentage change from a starting value to an ending value. Positive output means an increase and negative output means a decrease.
Formula and example
The result is ((ending − starting) / starting) × 100. From 50 to 60 gives 20%; from 50 to 40 gives -20%. Non-integer results display two decimals.
Input behavior
The starting value must be finite and nonzero; the ending value must be finite. Negative values are accepted, so interpretation across zero or from a negative baseline needs care. Reset restores 50 and 60.
Limits and privacy
This is relative change, not percentage-point difference, compound growth, annualization, or statistical significance. Calculation runs locally and inputs are not uploaded.
Frequently Asked Questions
- How is percentage change calculated?
- It's ((new value − old value) / old value) × 100. A positive result is an increase, a negative result is a decrease.
- What if the starting value is zero?
- Percentage change is undefined when the starting value is zero, since you'd be dividing by zero.
- Is this different from the percentage calculator?
- It's the same 'increase/decrease' mode, just as its own dedicated page for quicker access.