Percentage Calculator (percentage.gen.im) is a free online tool to calculate percentages.

### Calculate the percentage of a value

For to calculate 20% of 80 write first box 20, second box 80.

**Example:** If 10% students successful in the of 90 students, you must write first box 10, second box 90 to calculate how many students are successful.

**Solution:** `90 x 10 / 100 = 9`

**Solution:**

Calculate the percentage of a value.

What is**%**of ?

**=**

### How to calculate what percentage a number of another number

Write to first box 20, second box 80 to calculate what percentage 20 of 80.

**Solution:** `18 x 100 / 90 = 20`

**Solution:**

How to calculate what percentage a number is of another number

is what percent of ?**=**

**%**

### Calculate the percentage of the changed value

Write to first box, 20 second box 40 to calculate the percentage of the changed value.

**Solution:** `(90-60) / 60 x 100 = 50`

**Solution:**

What is the percentage increase/decrease

from to ?**=**

**%**

### To increase or decrease a specific percentage.

Write to first box 10, third box 80 than select second box (increase/decrease) to calculate increase or decrease 10 percantage of 80.

**Solution:** `70 + (70 x 10 / 100) = 77`

`70 - (70 x 10 / 100) = 63`

**Solution:**

To increase or decrease a specific percentage.

**%**of ?

**=**