**Knowing how to calculate the percentage of a number is absolutely necessary in many aspects of life.****Obviously, percentage calculations are very important in business and are often used a lot in work environments.**

In the next article we will see **how to calculate percentage**although we will also see several examples on the **percentage change and percentage difference**. Trying to simplify it as much as possible so that it is understood in the simplest way.

Table of Contents

## What is the percentage?

The percentage is a fraction of a 100% number. It means “Per hundred” and denotes a part of a total amount. For a better understanding, 45% would represent 45 out of 100 or 45% of the total amount.

It may also be referred to as “out of 100” or “per 100”. We could say “rain for 15 days out of every 100 days” or “rain 15% of the time”.

It is possible to write it in different ways. One way to do this is to represent it as a decimal. For example, 20% can be written as .20. It is possible to find the decimal version of a percentage by dividing the percentage by 100. Of course, a percentage can also be represented by the “%” sign.

## How to calculate the percentage

There are a few ways to get the percentage calculated. If we want to calculate, for example, the percentage of how many days it was sunny in a month, we will have to use the number of days in the month as the total number. Therefore, if we are going to evaluate the sunny days of the month of April, we are going to have to do it for 30 days.

Let’s say it was sunny 15 days out of 30 in April. We will have to divide 15 by 30 and we will have 0.5. If we continue with this example, we would multiply 0.5 by 100. This is equal to 50, which is obviously going to give us 50%. So we agree that the sunny days in April were 50%.

## Percent Types

There are three types of percentages which we can find in work environments:

**end number.****Find percentage.****Starting number.**

**end number**

“How much is 50% of 25?” For this problem, we already have the percentage and the total amount that we want to find the same for. So, we would move on to the second step in the previous section of this article. We are not going to divide, we are going to multiply the percentage by the whole number.

For this, we multiply 50%, or 0.5, by 25. This will give us 12.5. Which means the answer to this problem would be 12.5 which is 50% of 25.

**find percentage**

For a problem where it is necessary **find a percentage**, we could pose a question similar to “What percentage of 5 is 2?”. We will see a simple example, we are going to determine in percentage how much of 2 is part of 5. What we will have to do is divide the number that we want to convert into a total percentage.

This means that we are going to take the 2 and divide it by 5. The result would be 0.4. We then multiply 0.4 by 100 to arrive at 40%. This means that 2 is equal to 40% of 5.

**find start number**

In this case, the example question would be “45% of what is 2?” This is a more complicated problem, but one that we can solve with this formula. For this we are going to divide the total by the percentage in question. We will have to divide 2 by 45% or 0.45. Which would give us 4.4, leaving as a result that 2 is 45% of 4.4.

## How to Calculate Percentage Change

In the case of a percentage change, this is a mathematical value that denotes the degree of change over time. It is generally used in private and public finance to check the change in the price of a security over time. The formula can be applied to anything we need to measure over time.

So percentage change is the same as a given value. We can work out the percentage change by dividing the total value by the original, and then we’ll need to multiply it by one hundred. For example:

For a price or percentage increase: new price – old price/old price x 100For a price or percentage decrease: old price – new price/old price x 100

Let’s pretend a microwave was worth $100 last year, but now it’s worth $125. To find the price increase, we’ll need to subtract the old price from the new price: 125 – 100 = 25. Then we’ll have to run this by the price above: 25 divided by 100 equals 0.25. So we continue to multiply that number by 100: 0.25 x 100 = 25 or 25%. We concluded that the microwave increased by 25%.

## Calculate the percentage difference

It is possible to use percentages to buy two different things that are related. To serve as an example, if we want to see how much a product cost last year compared to how much it costs today. For this calculation I would give you the percentage difference between the prices of the two products.

The formula to calculate a percentage difference is as follows: |V1 – V2|/ [(V1 + V2/2] x 100. Here V1 is the same as the cost of the first product, while V2 would be the second.

Let’s pretend that one product cost $25 last year and a similar product costs $30 this year. To arrive at the percentage difference, we will need to subtract the costs from each other: 30 – 25 = 5. We then determine the average of the two costs (25 + 30 / 2 = 27.5). Now we are going to divide 5 by 27.5 = 0.18. Next, we multiply 0.18 times 100 = 18. This means that this year’s product cost is 18% higher than last year’s.

**Tip: very useful to use them as formulas in Excel.**

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