Percent Calculator
What is X% of Y?
What percent is X of Y?
Percentage Change (Increase/Decrease)
Understanding Percentage Calculations
A percentage is a number or ratio expressed as a fraction of 100. It is often denoted using the percent sign, "%". Percentages are used widely in mathematics, statistics, finance, and daily life to describe proportions, changes, and distributions.
1. How to Calculate a Percentage of a Number
This is the most common percentage task. For example, if you want to find 15% of 200, you use the following formula:
Value = (Percentage / 100) × Total
Example: Finding a 20% tip on a 50.00 bill. (20 / 100) * 50 = 10.00.
2. How to Find What Percent X is of Y
Use this when you have two numbers and want to know the proportional relationship between them. For instance, if you scored 40 out of 50 on a test, what is your percentage?
Percentage = (Part / Whole) × 100
Example: 40 divided by 50 is 0.8. Multiplying by 100 gives you 80%.
3. Calculating Percentage Change
Percentage change is essential for tracking growth, losses, or price fluctuations. It measures the difference between an old value and a new value relative to the original amount.
% Change = [(New Value – Original Value) / Original Value] × 100
Example: If a stock price goes from 100 to 125, the calculation is ((125 – 100) / 100) * 100 = 25% increase.
Common Uses for the Percent Calculator
- Sales & Discounts: Calculate how much you save during a "30% off" sale.
- Statistics: Determine the percentage of a population based on sample data.
- Academic Grades: Convert raw test scores into percentages.
- Business Growth: Compare year-over-year revenue to see the percentage increase.
- Chemistry & Nutrition: Calculate the percentage of ingredients or daily values.