Percentage Calculator
Seven clear ways to calculate percentages and changes.
X% of Y
—About This Calculator
Find a percentage of a value, compare two values, or apply a percentage increase or decrease. It is useful for discounts, markups, growth, and change over time.
How It Works
X% of Y is (X ÷ 100) × Y. Percentage change is (new − old) ÷ |old| × 100, while increasing or decreasing a number by X% uses number × (1 ± X ÷ 100).
Percent change = (new − old) ÷ |old| × 100
Example
Decreasing $80 by 25% gives 80 × (1 − 0.25) = $60.
Important Notes
Percentage comparisons need a nonzero starting or comparison value. A valid result can be negative or greater than 100%.