How to calculate percentage of a number? Simple interest formula: how to find the original value.

One percent is a hundredth of a number. This concept used when you need to indicate the ratio of a part to the whole. In addition, several values ​​can be compared as percentages, but be sure to indicate relative to which integer the percentages are calculated. For example, expenses are 10% higher than income or the price of train tickets has increased by 15% compared to last year's tariffs. A percent number above 100 means that the proportion is greater than the whole, as is often the case in statistical calculations.

Percentage as financial concept- payment from the borrower to the lender for providing money for temporary use. In business, the expression “work for interest” is common. In this case, it is understood that the amount of remuneration depends on profit or turnover (commissions). It is impossible to do without calculating percentages in accounting, business, and banking. To simplify calculations, an online interest calculator has been developed.

The calculator allows you to calculate:

  • Percentage of the set value.
  • Percentage of the amount (tax on actual salary).
  • Percentage of the difference (VAT from ).
  • And much more...

When solving problems using a percentage calculator, you need to operate with three values, one of which is unknown (a variable is calculated using the given parameters). The calculation scenario should be selected based on the specified conditions.

Calculation examples

1. Calculating the percentage of a number

To find a number that is 25% of 1,000 rubles, you need:

  • 1,000 × 25 / 100 = 250 rub.
  • Or 1,000 × 0.25 = 250 rubles.

To calculate using a regular calculator, you need to multiply 1,000 by 25 and press the % button.

2. Definition of an integer (100%)

We know that 250 rub. is 25% of a certain number. How to calculate it?

Let's make a simple proportion:

  • 250 rub. - 25%
  • Y rub. - 100 %
  • Y = 250 × 100 / 25 = 1,000 rub.

3. Percentage between two numbers

Let's say a profit of 800 rubles was expected, but we received 1,040 rubles. What is the percentage of excess?

The proportion will be like this:

  • 800 rub. - 100 %
  • RUB 1,040 – Y%
  • Y = 1,040 × 100 / 800 = 130%

Exceeding the profit plan is 30%, that is, fulfillment is 130%.

4. Calculation is not based on 100%

For example, 100% of customers come to a store consisting of three departments. In the grocery department - 800 people (67%), in the department household chemicals- 55. What percentage of buyers come to the household chemicals department?

Proportion:

  • 800 visitors – 67%
  • 55 visitors - Y%
  • Y = 55 × 67 / 800 = 4.6%

5. By what percentage is one number less than another?

The price of the product dropped from 2,000 to 1,200 rubles. By what percentage did the price of the product fall or by what percentage did 1,200 less than 2,000?

  • 2 000 - 100 %
  • 1,200 – Y%
  • Y = 1,200 × 100 / 2,000 = 60% (60% to the figure 1,200 from 2,000)
  • 100% − 60% = 40% (the number 1,200 is 40% less than 2,000)

6. By what percentage is one number greater than another?

The salary increased from 5,000 to 7,500 rubles. By what percentage did the salary increase? What percentage is 7,500 greater than 5,000?

  • 5,000 rub. - 100 %
  • 7,500 rub. - Y%
  • Y = 7,500 × 100 / 5,000 = 150% (in numbers 7,500 is 150% of 5,000)
  • 150% − 100% = 50% (the number 7,500 is 50% greater than 5,000)

7. Increase the number by a certain percentage

The price of product S is above 1,000 rubles. by 27%. What is the price of the product?

  • 1,000 rub. - 100 %
  • S - 100% + 27%
  • S = 1,000 × (100 + 27) / 100 = 1,270 rub.

The online calculator makes calculations much easier: you need to select the type of calculation, enter the number and percentage (in the case of calculation percentage- second number), indicate the accuracy of the calculation and give a command to begin actions.

Percent is one hundredth of a number taken as a whole. Percentages are used to indicate the relationship of a part to the whole, as well as to compare quantities.

Using a mathematical percentage calculator you can make all kinds of calculations using percentages. Rounds results to the required number of decimal places. What percentage is number X of number Y. What number is X percent of number Y. Adding or subtracting percentages from a number.

The online interest calculator allows you to perform the following operations:

Find the percentage of a number

To find the percentage p from a number, you need to multiply this number by the fraction p/100

Let's find 12% of the number 300:
300 12/100 = 300 0.12 = 36
12% of 300 is 36.

For example, a product costs 500 rubles and there is a 7% discount on it. Let's find the absolute value of the discount:
500 7/100 = 500 0.07 = 35
Thus, the discount is 35 rubles.

What percentage is one number of another?

To calculate percentage numbers, you need to divide one number by another and multiply by 100%.

Let's calculate what percentage the number 12 is from the number 30:
12/30 100 = 0.4 100 = 40%
The number 12 is 40% of the number 30.

For example, a book contains 340 pages. Vasya read 200 pages. Let's calculate what percentage of the entire book Vasya read.
200/340 100% = 0.59 100 = 59%
Thus, Vasya read 59% of the entire book.

Add percentage to number

To add to a number p percent, you need to multiply this number by (1 + p/100)

Add 30% to the number 200:
200 (1 + 30/100) = 200 1.3 = 260
200 + 30% equals 260.

For example, a swimming pool subscription costs 1000 rubles. Starting next month they promised to raise the price by 20%. Let's calculate how much a subscription will cost.
1000 · (1 + 20/100) = 1000 · 1.2 = 1200
Thus, the subscription will cost 1200 rubles.

Subtract the percentage from the number

To subtract from a number p percent, you need to multiply this number by (1 - p/100)

Subtract 30% from the number 200:
200 · (1 - 30/100) = 200 · 0.7 = 140
200 - 30% equals 140.

For example, a bicycle costs 30,000 rubles. The store gave it a 5% discount. Let's calculate how much the bike will cost taking into account the discount.
30000 · (1 - 5/100) = 30000 · 0.95 = 28500
Thus, the bike will cost 28,500 rubles.

What percentage is one number greater than another?

To calculate how many percent one number is greater than another, you need to divide the first number by the second, multiply the result by 100 and subtract 100.

Let's calculate how many percent the number 20 is greater than the number 5:
20/5 100 - 100 = 4 100 - 100 = 400 - 100 = 300%
The number 20 is 300% greater than the number 5.

For example, the boss’s salary is 50,000 rubles, and the employee’s salary is 30,000 rubles. Let's find out how many percent the boss's salary is greater:
50000/35000 100 - 100 = 1.43 * 100 - 100 = 143 - 100 = 43%
Thus, the boss's salary is 43% higher than the employee's salary.

What percentage is one number less than another?

To calculate how many percent one number is less than another, you need to subtract from 100 the ratio of the first number to the second, multiplied by 100.

Let's calculate what percentage is the number 5 less number 20:
100 - 5/20 100 = 100 - 0.25 100 = 100 - 25 = 75%
The number 5 is 75% less than the number 20.

For example, freelancer Oleg completed orders worth 40,000 rubles in January, and 30,000 rubles in February. Let's find how many percent less Oleg earned in February than in January:
100 - 30000/40000 100 = 100 - 0.75 * 100 = 100 - 75 = 25%
Thus, in February Oleg earned 25% less than in January.

Find 100 percent

If the number x This p percent, then you can find 100 percent by multiplying the number x on 100/p

Let's find 100% if 25% is 7:
7 100/25 = 7 4 = 28
If 25% equals 7, then 100% equals 28.

For example, Katya copies photos from her camera to her computer. In 5 minutes, 20% of the photos were copied. Let's find how long the copying process takes:
6 100/20 = 6 5 = 30
We find that the process of copying all photos takes 30 minutes.

Instructions

To calculate percentages of a number on a regular one, follow the following sequence of actions. Type the percentage number on the keyboard (you don’t need to press the “%” button yet). Click on any of the arithmetic symbols (“+”, “-”, “x”, “/” - in this case, this button is used as a separator when entering numbers). Now type on the calculator the number from which you want to calculate the percentage. Click on the "%" button. The desired result will be displayed on the calculator indicator.

You can also calculate percentages of a number using a computer. To do this, start standard Windows. To do this, click “Start” -> “Run” -> type “calc” -> OK. If the calculator was loaded in “Engineering” view, then set it to “Normal” mode (“View” -> “Normal”). After this, count from the number, just as described in the previous paragraph of the instructions.

To calculate percentages of a number in MS Excel, type the following sequence of characters: “=” “number” “*” “number of percents” “Enter”. So, for example, to calculate 13% of 10000, enter the following formula in the required one: =10000*13% and press “Enter”. If you have done everything, then the number 1300 will appear instead.

Video on the topic

Sources:

  • percentage of number calculator

Percent in Latin (“pro centum”) means one hundredth. Therefore, if you need a certain percentage of a certain amount of money, this means that you need to determine how many hundredths of the amount the specified percentage contains. If you can’t do the math in your head, the easiest way is to calculate the percentage using a calculator.

Instructions

Use, for example, standard Windows OS to calculate from a given amount. The link to launch it can be found in the main menu of the system - open it by pressing the WIN key or clicking the “Start” button. You need to go to the “All Programs” section, expand the “Standard” subsection in it and click on the “Calculator” line. However, hackers are not very fond of “mouse computing” and if you also want to feel a little like a hacker, then press the key combination WIN + R, type the command calc and press Enter. Both methods launch the same Windows calculator.

Find one hundredth of the entered number. To do this, use the slash key on your keyboard or on-screen interface, and then enter the number 100.

Multiply one hundredth of the amount by a known quantity. To do this, press on your keyboard or click on the star button on the screen, and then enter the percentage.

Complete the calculation of the percentage of the amount by pressing the keyboard or clicking the equal sign button on the screen. The calculator will show you numeric expression a specified percentage of the entered amount.

Having access to the Internet, you can do without a calculator when solving such a problem. There are many of its analogues on the Internet that allow you to perform the necessary calculations directly in the browser window. If you don’t have time to search for such services, then enter the required mathematical expression directly in the request field search engine Google and get immediate results. For example, to calculate 13% of the amount of 25,512 14 kopecks, enter the following query: “25521.14 / 100 * 13”.

Video on the topic

note

How to calculate percentages. In everyday life, you often need to be able to determine what percentage a given number is from the whole part. This is a mathematical operation that takes place in high school, may come in handy when calculating all kinds of loan payments, calculating ratios for any purchases, and at work we regularly have to use comparative characteristics, expressed as a percentage.

Helpful advice

How to calculate interest? April 4, 2012. Category: Training. No comments. Surely you have come across such a concept as “percentage” more than once. And some even needed to somehow calculate it. The first way is to count in your head: The number from which you need to find the percentage must be divided by one hundred and then multiplied by the number of percentages. Or immediately multiply the number by percentages expressed in hundredths (percent divided by one hundred). For example, you need to find 28% of the number 924.

Sources:

  • how to calculate interest from an amount

Opening a deposit is a popular solution to ensure the safety of savings and increase them. The profitability of a deposit depends on the interest rates established on it, as well as the method of their calculation. That is why it is important to be able to calculate them correctly.

You will need

  • Calculator.

Instructions

To calculate interest on a deposit, please specify how it is calculated. Thus, they can be accrued at the end of the deposit term, quarterly or monthly. There are also two types of interest - simple and compound (with capitalization).

When simple interest is calculated, at a certain frequency established in the agreement, they are transferred to a separate account and are not added to the deposit amount. Calculating them is quite simple. To do this, multiply the initial deposit amount by the annual rate and the number of days for which the deposit is open. Then the resulting amount will be divided by 100 and the number of days in the year (365 or 366). For example, a deposit in the amount of 100 thousand rubles. open for 90 days with a rate of 9.8% per annum. The return on the deposit will be 2416.4 rubles. (100*9.8*90/365/100). If the deposit is opened for a year, you simply need to multiply the deposit amount by the percentage.

For a deposit with capitalization, the accrued interest is added to the deposit amount within the terms specified in the agreement. Most often - monthly or quarterly. As a rule, the investor has a choice - to capitalize the interest or withdraw the yield. But subject to capitalization, the deposit amount increases, and accrued interest increases accordingly. To calculate the deposit amount, taking into account interest, it is necessary to multiply the initial investment amount by the annual rate and by the number of days for which the bank carries out capitalization and divide by the number of days in a year and by 100. For example, with a deposit of 100 thousand rubles. at a rate of 9.8% with monthly capitalization of interest, the amount of interest for January will be 832.3 rubles. (100*9.8*31/365). It turns out that for February interest will be accrued on the deposit amount of 100,832.3 rubles. Further calculations are carried out similarly. If you want to calculate the amount of interest on a deposit for a specified period, you must multiply the initial deposit amount by ((1 + annual interest rate * number of days / number of days in a year / 100) to the power (number of interest periods - 1).

In this short video lesson we will learn how to solve problems involving percentages using a special formula called the simple interest formula. Let's formalize this formula as a theorem.

The simple interest theorem. Let's assume that there is a certain initial value x, which then changes by k%, and a new value y is obtained. Then all three numbers are related by the formula:

A plus or minus is placed in front of the coefficient k depending on the conditions of the problem. If, according to the condition, the value x increases, then there is a plus in front of k. If the value decreases, then the coefficient k is preceded by a minus.

Despite the apparent intricacy of this formula, many problems can be solved very quickly and beautifully with its help. Let's try.

Task. The price of the product was increased by 10% and amounted to 2970 rubles. How many rubles did the product cost before the price increase?

To solve this problem using the simple interest formula, we need three numbers: the original value x, the percentage k, and the final value y. From all three numbers, we know the percentage k = 10 and the final value y = 2970. Please note: 2970 is exactly the final price, i.e. y. Because according to the conditions of the problem, the initial price of the product is unknown (it is precisely what needs to be found). But then it was increased, and only then it amounted to 2970 rubles.

So, we need to find x, i.e. original value. Well, we substitute our numbers into the formula and we get:

We add the numbers in the numerator and get:

We reduce one zero each in the numerator and denominator, and then multiply both sides of the equation by 10. We get:

11x = 29,700

To find x from this simplest linear equation, you need to divide both sides by 11:

x = 29,700: 11 = 2700

As you can see, it's quite big numbers, so you can’t carry out such calculations in your head. If you encounter such a problem on the Unified State Exam, you will have to divide it into a corner. In this case, everything was divided without a remainder, and we received the value x:

x = 2700

This is how much the product cost before the price increase. And it was this number that we needed to find according to the conditions of the problem. So that’s it: the problem is solved. Moreover, it was solved not “outright”, but using the simple interest formula - quickly, beautifully and clearly.

Of course, this problem could have been solved differently. For example, through proportions. Or the exotic coefficient method. But it will be much better and more reliable if you have several techniques in your arsenal for solving any percentage problem. So be sure to practice using this formula.

One of the basic concepts of mathematics is percentage. In order to understand what a percentage is, it is enough to divide the given whole value by one hundred. One hundredth would be one percent (denoted 1%). Both in the exact and economic sciences, and in other areas of life, percentages are used to indicate shares in relation to the whole. In this case, the whole itself is designated as 100%. In some cases, it is used when comparing two values: for example, sometimes the cost of goods is not compared in monetary units, but is estimated by how many% the price of one product is more or less than the price of another. The term has also become widespread in banking and is mostly used as a synonym for interest rate.

Rule for finding percentages of a number

Calculating percentages of a whole is one of the basic mathematical operations, and is also often used in Everyday life. The rule for finding percentages of a number states that to solve such a problem, it must be multiplied by the amount of % specified in the conditions, after which the resulting result is divided by 100. You can also divide the number by 100, and the resulting result is multiplied by the specified amount of %. It is important to remember one more thesis: if the percentage specified by the conditions exceeds 100%, then the resulting numerical value is always greater than the initial (specified) one - and vice versa.

The rule for finding a number by its percentage

Exists reverse rule finding a number by its percentage. In order to obtain the result of such a mathematical operation (the second of the three basic types of problems for percentage calculations), it is necessary to divide the number specified in the conditions by a given percentage value, after which the resulting result is multiplied by 100. In this case, the first action is to calculate the number of units of the original value in 1 %, and the second - in general (that is, 100%). If the number of % exceeds 100, then the result obtained will always be less than the numerical value specified by the conditions of the problem - and vice versa.

The rule for finding the percentage expression of a number from another

The third basic type of mathematical problems involving percentage calculations are those in which it is necessary to use the rule for finding the percentage expression of a number from another (or the ratio of two quantities). It says that to solve it is necessary to divide the second number by the first, after which the resulting result is multiplied by one hundred. Such a ratio shows how many % one numerical value is from another (that is, in fact we are talking about the relationship between two numerical values, expressed in %).



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