Answer
30.00
Percentage Calculator
Solve common percentage calculations, including increase, decrease, and percent change.
Key Terms (Click to expand)
Percentage (%)
A way to express a value as parts per hundred.
Base value
The denominator used to compute a percentage relationship.
Percent change
The signed change from start value A to end value B, relative to A.
Percentage points
Absolute difference between two percentages, not a relative percent change.
Tool
Percentage detail breakdown
| Mode | What is X% of Y? |
|---|---|
| Formula used | (X / 100) * Y |
| Explanation | Calculates what X percent of Y equals. |
Methodology
The calculator uses standard percentage formulas based on the selected mode:
- What is X% of Y:
(X / 100) * Y - X is what % of Y:
(X / Y) * 100 - % increase from A to B:
((B - A) / A) * 100 - % decrease from A to B:
((A - B) / A) * 100 - % change from A to B:
((B - A) / A) * 100
Worked Example
Using What is X% of Y? with A = 15 and B = 200, the result is 30.00 .
Assumptions and Limitations
- Mode-specific formulas are applied exactly as entered, with no domain-specific adjustment rules.
- Some modes require a non-zero base value to avoid division-by-zero results.
- Negative values are allowed and can produce negative percentage outcomes.
FAQ
What is the difference between percent change and percentage points?
Percent change is relative to a base value, while percentage points are an absolute gap between percentages.
How do I calculate a discount percentage?
Use percentage decrease mode with original price as A and discounted price as B.
Can I use negative numbers?
Yes. Negative inputs are supported, but interpretation depends on context and selected formula mode.