6 ways to calculate percentage of an amount with and without calculator

2024 Author: Malcolm Clapton | [email protected]. Last modified: 2023-12-17 03:44

The simplest formulas will help you find out if discounts are profitable and not upset the proportion of a great recipe.

1. How to calculate the percentage by dividing the number by 100

This will give you the numeric equivalent of 1%. Then it all depends on your goal. To calculate the percentage of the amount, multiply it by 1%. To convert a number to a percentage, divide it by 1%.

Example 1

You walk into a supermarket and see a special offer for coffee. Its usual price is 458 rubles, now there is a 7% discount. But you have a store card, and a pack of it will cost 417 rubles.

To understand which option is more profitable, you need to translate 7% into rubles.

Divide 458 by 100. To do this, you just need to shift the comma that separates the integer part of the number from the fractional part two positions to the left. 1% is equal to 4.58 rubles.

Multiply 4.58 by 7 and you get 32.06 rubles.

Now it remains to subtract 32.06 rubles from the regular price. For the promotion, coffee will cost 425.94 rubles. This means that it is more profitable to buy it with a card.

Example 2

You can see that the game on Steam costs 1,000 rubles, although it was previously sold for 1,500 rubles. You are wondering how much percent the discount was.

Divide 1,500 by 100. By moving the comma two places to the left, you get 15. This is 1% of the old price.

Now divide the new price by 1%. 1,000/15 = 66.6666%.

100% - 66, 6666% = 33, 3333%. This discount was provided by the store.

2. How to calculate the percentage by dividing the number by 10

This method is similar to the previous one, but it is much faster to calculate with it. But only if we are talking about percentages that are multiples of five.

First you find the size 10%, and then you divide or multiply it to get the percentage you want.

Example

Let's say you deposit 530 thousand rubles for 12 months. The interest rate is 5%, capitalization is not provided. You want to know how much money you will take in a year.

First of all, you need to calculate 10% of the amount. Divide it by 10 by moving the comma one character to the left. You will receive 53 thousand.

To find out how much is 5%, divide the result by 2. That's 26.5 thousand.

If the example were about 30%, you would have to multiply 53 by 3. To calculate 25%, you would have to multiply 53 by 2 and add 26.5.

In any case, it is quite easy to operate with such large numbers.

3. How to calculate percentages by proportion

Proportioning is one of the most useful skills you were taught in school. With it, you can calculate any percentage. The proportion looks like this:

Or you can write it like this: a: b = c: d.

Usually, the proportion reads "a refers to b as well as c refers to d". The product of the extreme terms of the proportion is equal to the product of its middle terms. To find out the unknown number from this equality, you need to solve the simplest equation.

Example 1

Let's use a quick brownie recipe for the calculation example. You want to make it and bought a suitable 90 g bar of chocolate, but you couldn't resist and took a bite or two. Now you only have 70 g of chocolate, and you need to know how much butter to put in instead of 200 g.

First, we calculate the percentage of the remaining chocolate.

90 g: 100% = 70 g: X, where X is the mass of the remaining chocolate.

X = 70 × 100/90 = 77.7%.

Now we make up the proportion to find out how much oil we need:

200 g: 100% = X: 77.7%, where X is the required amount of oil.

X = 77.7 × 200/100 = 155.4.

Therefore, you need to put about 155 g of butter in the dough.

Example 2

The proportion is also suitable for calculating the profitability of discounts. For example, you see a blouse for 1,499 rubles with a 13% discount.

First, find out how much the blouse costs in percentage. To do this, subtract 13 from 100 and get 87%.

Make the proportion: 1 499: 100 = X: 87.

X = 87 × 1 499/100.

Pay 1,304.13 rubles and enjoy wearing a blouse.

4. How to calculate percentages using ratios

In some cases, you can use simple fractions. For example, 10% is 1/10 of a number. And to find out how much it will be in numbers, it is enough to divide the whole by 10.

• 20% - 1/5, that is, you need to divide the number by 5;
• 25% - 1/4;
• 50% - 1/2;
• 12, 5% - 1/8;
• 75% is 3/4. So, you have to divide the number by 4 and multiply by 3.

Example

You found pants for 2,400 rubles with a 25% discount, but you only have 2,000 rubles in your wallet. To find out if there is enough money for a new thing, carry out a series of simple calculations:

100% - 25% = 75% - the cost of trousers as a percentage of the original price after applying the discount.

2,400 / 4 × 3 = 1,800. That is how much the trousers cost.

5. How to calculate interest using a calculator

If life is not nice to you without a calculator, all calculations can be done with its help. And you can do it even easier.

• To calculate the percentage of an amount, enter a number equal to 100%, a multiplication sign, then the desired percentage and a% sign. For the coffee example, the calculations would look like this: 458 × 7%.
• To find the amount minus interest, enter the number equal to 100%, minus, the percentage and the% sign: 458 - 7%.
• Similarly, you can add, as in the example with a deposit: 530,000 + 5%.

6. How to calculate interest using online services

Not all percentages can be calculated in your head and even on a calculator. When it comes to deposit returns, mortgage overpayments or taxes, complex formulas are required. They are included in some online services.

Planetcalc

The site contains various calculators that calculate not only percentages. There are services for lenders, investors, entrepreneurs and all those who do not like to count in their heads.

Calculator - help portal

Another service with calculators for every taste.

Allcalc

Catalog of online calculators, 60 of which are designed for calculating finance. You can calculate taxes and penalties, the amount of subsidies for housing and communal services and much more.