# Percentage change calculator

This percentage change calculator will show the result of an increase or decrease by X percent.

## Percentage change

What does a percentage change mean in reality. First of all percentage is another word for a hundredth (1/100). It will be easier with some examples.

### Increase a number with X %

The first example will illustrate a percentage increase. Let say you have 100 balls. Each and every ball represents 1 % (1 hundredth). If you increase the 100 balls with 10% (10 hundredth, 10 balls) you’ll have 110 balls.

### Decrease a number with X %

To illustrate a decrease with X% we start with 100 balls like the first example. If you reduce 100 balls with 10% it is the same thing as reducing the number with 10 balls because 10 balls is 10 hundredth of 100 balls. So, a decreasing 100 by 19 is 90.

### Increase a number with X% and then decrease with 10%

The last example illustrates what happens if we first increase a number with 10% and then reduce it with 10%.

Spontaniously you may think the answer would be 100, because if you add 10% and then reduce with 10% the change would be zero. But it isn’t that easy.

Like before we start with the 100 balls. An increase with 10% gives us 110 balls. Since the number of balls now is 110 we have to check how many balls 1% is now. Because of the 10% increase 1% now is 1,1 balls. Consequently 10% of 110 is 11. When we now decrease 10% we now have to decrease 10% (11 balls) from 110. The result of increasing 100 with 10% and then decreasing it with 10% is 99. In other words is the reduction of 10% greater than adding the 10% in the first place. The explanation is quite simple: the 10 % we reduce is “worth” more because they are based on 110 balls instead of the original 100 that we started with. The VAT calculator is a kind of percentage change calculator.