In this article we will learn percentage (%).

Percentage is per-cent which means parts per hundred.

One percent is equal to 1/100 fraction:

1% = 1/100 = 0.01

Ten percent is equal to 10/100 fraction:

10% = 10/100 = 0.1

Fifty percent is equal to 50/100 fraction:

50% = 50/100 = 0.5

One hundred percent is equal to 100/100 fraction:

100% = 100/100 = 1

One hundred and ten percent is equal to 110/100 fraction:

110% = 110/100 = 1.1

### Percent sign

The percent sign is the symbol: **%**

It is written to the right side of the number: 50%

### Percentage Definition

Percentage is a value that represents the proportion of one number to another number.

1 percent represents 1/100 fraction.

100 percent (100%) of a number is the same number:

100% × 80 = 100/100×80 = 80

50 percent (50%) of a number is half of the number:

50% × 80 = 50/100×80 = 40

So 40 is 50% of 80.

### Percentage of a Value Calculation

x% of y is calculated by the formula:

percentage value = x% × y = (x/100) × y

**For example:**

Find 30% of 100.

30% × 100 = (30 / 100) × 100 = 30

### Percentage Calculation

The percentage of x from y, is calculated by the formula:

percentage = (x / y) × 100%

**For example:**

The percentage of 50 out of 70.

(50 / 70) × 100% = 71,42%

### Percentage Change (increase/decrease)

Percentage change from x1 to x2 is calculated by the formula:

percentage change = 100% × (x2 – x1) / x1

When the result is positive, we have percentage growth or increase.

**For example:**

Percentage change from 40 to 70 (increase).

100% × (70 – 40) / 40 = 75%

When the result is negative, we have percentage decrease.

**For example:**

Percentage change from 90 to 30 (decrease).

100% × (30 – 90) / 30 = -200%