How to calculate percentage
Calculating percentages is a fundamental mathematical operation that is used in many areas of daily life. For example, when shopping and calculating discounts, or when studying economics to analyze price variations.
In this article, we will see how to calculate percentages in a simple and fast way, without resorting to complicated mathematical calculations. Let's start by defining what a percentage is.
What is a percentage?
A percentage is a numerical value expressed in hundredths relative to a total. For example, if we have 10 apples and eat 3, we can say that we have eaten 30% of the total apples.
To calculate the percentage of a certain value relative to the total, simply divide the value by the total and multiply by 100.
- Example: If we have 15 students in class and only 8 are male, we can calculate the percentage of male students as follows: (8 / 15) x 100 = 53.33%
Now that we understand what a percentage is and how to calculate it, let's see some practical examples to better understand how to apply it in everyday life.
What is a percentage?
Before starting to calculate percentages, it is important to understand exactly what a percentage is.
In simple terms, a percentage represents part of a whole out of 100. For example, if we say that 20% of students got high grades, it means that out of 100 students, 20 got high grades.
Percentages are widely used in everyday life and in many sectors such as economics, finance, and marketing. Knowing how to calculate percentages correctly is therefore essential for many activities.
To calculate a percentage, you must first know two values: the total value (or base) and the partial value (or percentage).
- The base represents the total value to which we refer. For example, if we are talking about the total sales of a store in a month, the base will be the total sales made in that month.
- The percentage represents instead the part of the base that we want to calculate. For example, if we want to know what percentage of total sales was made by a particular product, the percentage will be represented by the sales of that product in the total sales of the store.
Once these two values are known, we can proceed with calculating the percentage using a simple mathematical formula.
How do you calculate the percentage of a number?
To calculate the percentage of a number, it is necessary to know two values: the value of the original number and the value of the percentage you want to calculate.
The first step is to convert the percentage into a fraction or decimal. For example, if you want to calculate 20% of a number, divide 20 by 100, obtaining either the decimal value 0.2 or the fraction 1/5.
Once the percentage is converted, simply multiply it by the value of the original number to obtain the desired result. For example, if you want to calculate 20% of 50, you need to multiply 0.2 by 50, resulting in a result of 10.
Example:
- Calculate 15% of 120
- Convert the percentage to decimal: 15/100 = 0.15
- Multiply the decimal value by the original number: 0.15 x 120 = 18
Alternatively, you can use a mathematical formula to calculate the percentage of a number:
(percentage / 100) * original number = resultExample:
- Calculate 25% of 80 using the formula
- (25 / 100) * 80 = 20
It is important to remember that percentages can also be calculated in reverse, starting from the result and looking for the original value. In this case, you must divide the result by the percentage converted into a decimal or fraction.
Example:
- Find the original number if 20% of it equals 30
- Convert the percentage to decimal: 20/100 = 0.2
- Divide the result by the decimal percentage: 30 / 0.2 = 150
How to calculate the original value of a percentage?
Calculating the original value of a percentage means finding the whole number that corresponds to that percentage. For example, if you know that 20% of a number is equal to 50, how can you find the original number?
Here's how:
- Multiply the percentage by the whole number it is applied to.
- Divide the result by 100.
Example:
If we want to know what is the whole number from which a percentage of 20% derives, we must multiply the percentage (20%) by the total (x):
20% * x = ?Then we divide by 100:
(20% * x) / 100 = ?Now we substitute the percentage with its corresponding decimal value (0.20):
(0.20 * x) / 100 = ?At this point we can simplify by eliminating the final zero in division:
(0.20 * x) = ?Finally, solve the equation by isolating x:
x = ? / 0.20x = ? * 5x = ?So, if 20% of a number equals 50, then that original number is:
x = 50 / 0.20x = 250So the original value is 250.
Practical examples of percentage calculation
To better understand how to calculate percentage, let's see some practical examples:
Example 1: Calculate 20% of 50 euros
To calculate 20% of 50 euros, multiply 50 by 20 and divide the result by 100:
(50 x 20) / 100 = 10The result is 10 euros. So 20% of 50 euros is equal to 10 euros.
Example 2: Calculating the discount percentage
Suppose a product originally costs 80 euros and is on sale with a 25% discount. To calculate the discounted price, we need to subtract the percentage of the discount from the original price:
80 - (80 x 25) / 100 = 60The discounted price is therefore 60 euros.
Example 3: Calculating the percentage increase
Suppose a company has increased its earnings from 500,000 euros to 600,000 euros. To calculate the percentage increase, we need to divide the difference between the two numbers by the original number and then multiply by 100:
((600,000 - 500,000) / 500,000) x 100 = 20%The percentage increase is therefore 20%.
- With these practical examples, we hope to have made the concept of percentage calculation clearer. Remember that percentages can be useful in many areas of everyday life, from finance to mathematics.
Conclusions
As we have seen, percentage calculation is a fundamental concept in mathematics and finance. Knowing how to calculate percentages can be very useful in everyday life, for example for discounts during purchases or to understand the increase in a company's revenues.
Always remember to pay attention to units of measurement and use the correct formula for the type of problem you need to solve. With a little practice, percentage calculation will become as easy as counting to ten!
Michael Anderson - Software Engineer
My name is Michael Anderson, and I work as a computer engineer in Midland, Texas.
My passion is sharing my knowledge in various areas, and my purpose is to make education accessible to everyone. I believe it is essential to explain complex concepts in a simple and interesting way.
With GlobalHowTo, I aim to motivate and enrich the minds of those who want to learn.
