Published and reviewed by ToolSyn Editorial • Updated July 19, 2026
A percentage expresses a value as a share of 100. The correct formula depends on whether you are finding a percentage of a number, comparing a part with a total, or measuring change over time.
How to find a percentage of a number
Percentage amount = (Percentage ÷ 100) × NumberHow to find what percentage one number is of another
Percentage = (Part ÷ Total) × 100How to calculate percentage increase
Percentage increase = ((New − Original) ÷ Original) × 100How to calculate percentage decrease
Percentage decrease = ((Original − New) ÷ Original) × 100Percentage for marks
Add obtained marks, divide by the combined total marks and multiply by 100. Do not convert the percentage into GPA unless the institution publishes an official conversion.
Percentage for discounts
Multiply the original price by the discount rate and divide by 100 to find the saving. Subtract the saving from the original price to find the sale price.
Common mistakes
- Using the wrong value as the base.
- Dividing by zero in comparison questions.
- Adding successive discounts instead of applying them one after another.
- Confusing percentage points with percentage change.
Frequently asked questions
What is 20% of 500?
20% of 500 is 100.
What percentage is 45 out of 60?
45 out of 60 is 75%.
What is the difference between percent and percentage points?
Percentage points describe the direct difference between two percentages, while percentage change compares that difference with the original percentage.
Can a percentage be greater than 100?
Yes. A value can be more than 100% of the comparison value.