When do you need a percentage calculation?
- A is what % of B: test score ratios, goal-completion rates
- Percentage value of a base number: discount amounts, sales tax, tips
- Percentage change: revenue growth, weight-loss rate, stock price movement
Example
An $800 item discounted to $680: (680 β 800) Γ· 800 Γ 100 = β15% (a 15% discount).
Frequently Asked Questions
What does a negative percentage change mean?
It means the new value is smaller than the previous value β a decrease. For example, β15% means it decreased by 15%.
Is a percentage point (pp) different from a percent (%)?
Yes. A percentage point is the simple difference between two percentages (e.g. 10% β 15% is a 5pp increase), while a percent is the relative rate of change (in this case, a 50% increase).