Percentage Increase/Decrease Calculator
Bidirectional % change between two numbers — or apply a known % to a base value.
About the Percentage Increase/Decrease Calculator
Percentage Increase/Decrease Calculator is two tools in one: compare two numbers to see the percentage jump (or drop) between them, or apply a known percentage to a base number to find the new value.
How to use
- In the top row, enter the original value and the new value to see the percentage change.
- In the bottom row, enter a base value and a percentage (positive or negative) to apply it.
- Results appear in the output panel with direction and a short explanation.
Benefits & key features
- Handles both directions (increase and decrease) in a single tool.
- Shows the raw difference alongside the percentage — useful for financial work.
- Edge-case safe (zero original, negative bases) with clear error messages.
- Ideal for sales growth, investment returns and exam-score tracking.
Pro tip
When comparing sales year-over-year, a 50% drop followed by a 50% rise does NOT return to the original number — this tool makes that truth obvious.