## Percentage Calculation Explained

A percentage is a number or ratio expressed as a fraction of 100.

The percent value is computed by multiplying the numeric value of the ratio by 100.

The general formula for calculating percentage is: X/Y = P x 100, when X and Y are numbers and P is the percentage.

### Percentage Calculation – Examples

- If 50% of the total number of apples in a bag are green, that means that 50 out of every 100 apples are green. If there are 10 apples, then 5 of them are green.
- An increase of $0.1 on a price of $2 is an increase by 5% (0.1/2=0.05=5%).

## Percentage Increase and Decrease

An percentage increase or decrease is relative to the initial number or value of that quantity.

### Percentage Increase and Decrease Examples

- An increase of 10% in a quantity means that the final amount is 110% of the initial amount (100% of initial + 10% of increase = 110% of initial).
- A decrease of 20% means the final amount is 80% of the original (100%–20%=80%).

## Using the Percentage Calculator

The percentage calculator can be used to calculate:

- What is P percent of X? (For example: What is 10% of 500?)
- The number X is what percent of the number Y? (For example: 10 is what percent of 50?)
- What is the percentage change from X to Y? (For example: What is the percentage change from 100 to 120).