# How To Calculate Percentage

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87 How To Calculate Percentage: You may heard in news that this year in USA rainfall was 15% above the average, unemployment rate decline by 2% or banker’s bonuses slashed by 10% these all are cases of percentage. Calculating percentage is not just only important for students who need to pass their school math test but it is also vital for everyone to know how to calculate percentage, if you know how to calculate percentage then your daily life math problems would be solved easily. In this article we have explained 5 cases of calculating percentage.

## What is Percentage

Percentage literally means parts per 100 or out of one hundred we use this % symbol for percent; percentage is expressing a proportionate part of a total for example 35% is same as 35/100, 0.35 or 35:100. Percentage is useful to calculate discounts, bank interest amount, making sales presentation, show percentage in pie chat, calculate rate of inflation and so on. It’s a way to express a number as a part of whole for example you have 9 apples and you ate 1 apple now what percentage of apples you have eaten as 9 apples is equal to 100% so what is 1 apple equal to (%)?, to find out the answer you need to simply divide apple you ate by total numbers of apples, which is 1/9 = 0.11 but question says what is the percentage of eaten apple so you need to multiply 0.11 with 100 which give 11% so it means that you ate 11% apple. Percentage can be converted into decimal just divide “percentage value” by 100 for example – convert 10.5% into decimal so 10.5/100 = 0.105 (this value is in decimal).

### How To Calculate Percentage

There are several problems related to percentage, here we have covered all possible percentage problems.

Case 1: How To Calculate Unknown Percentage (when you know partial amount & whole amount).

Case 2: How To Calculate Unknown Partial Amount (when you know percentage & whole amount).

Case 3: How To Calculate Unknown Whole Amount (when you know percentage & partial amount).

Case 4: How To Calculate Discounts.

Case 5: How To Calculate Sales Performance in Percentage.

### Case 1: How To Calculate Unknown Percentage

In this type of problem you need to find out the percentage, as in question there is no percentage value is given for example – “15 (partial amount) is what percent of 200 (whole amount)”. Here we explained in simple steps to find out unknown percent.

• Firstly observed the question suppose the question is “15 is what percent of 200”, in this question “is” related with the partial amount and “of” related with the whole number and “what” related unknown value (percentage to find out). In question 15 is partial value and 200 is whole value.
• Formula to find out unknown percent: unknown percent = partial / whole * 100, for example “15 is what percent of 200” so divide 15 by 200 you will get 0.075
• Now multiply this result 0.075 by 100 to find out unknown percentage, for example 0.075 * 100 and you will get 7.5% (so 15 is 7.5% of 200).

Example 1: 5 is what percent of 50?

Solution: 5 / 50 = 0.1

0.1 * 100 = 10% (so 5 is 10% of 50)

Example 2: Suppose you saved \$200.50 and your annual income is \$3500.50 so what percent of amount you have saved out of your annual income?

Solution: 200.50 / 3500.50 = 0.057

0.057 * 100 = 5.7% (so you have saved 5.7% of amount out of your annual income)

### Case 2: How To Calculate Unknown Partial Amount

In this type of problem you need to find out the partial amount and here we have explained in simple steps to find out unknown partial amount.

• Firstly observed the question, if in question “what” and “is” closely related then it is case of “unknown partial amount”. For example – what is the 15% of 225, here 15% is a percentage and 225 is whole amount and you need to find out partial amount.
• For example – what is the 15% of 225? so 15 / 100 = 0.15 now multiply 0.15 with 225 and answer is 33.75 (so 33.75 is the 15% of 225).

Example 1: What is 25% of \$150?

Solution: Unknown partial amount = Percentage (25%) * whole amount (150) (if you using calculator)

Or

25 / 100 = 0.25 (to covert percentage into decimal, simply divide by 100)

0.25 * 150 = 37.5 (so \$37.5 is the 25% of \$150)

Example 2: Suppose you will need 75% marks in order to pass the exam and exam is 300 of marks, so what is the passing marks?

Solution: Unknown partial amount = Percentage (75%) * whole amount (300) (if you using calculator)

Or

75 / 100 = 0.75 (to covert percentage into decimal, simply divide by 100)

0.75 * 300 = 225 (so passing marks for exam is 225)

Example 3: Suppose you get pay check of \$1500 and 20% of your pay check go to the tax and you need to find out what amount you should pay for the tax?

Solution: Unknown partial amount = Percentage (20%) * whole amount (1500) (if you using calculator)

Or

20 / 100 = 0.2 (to covert percentage into decimal, simply divide by 100)

0.2 * 1500 = 300 (so you will pay \$300 as tax amount)

### Case 3: How To Calculate Unknown Whole Amount

In this type of problem you need to find out the whole amount, in question there is no whole amount is given for example 45 (partial amount) is 15% (percentage) of what amount? Here we have explained in simple steps to find out unknown whole amount.

• Firstly observed the question, if in question “of what” come together it means that is unknown whole amount problem. For example 45 is 15% of what amount? In this question 45 is partial amount & 15% is percentage value and you need to find out whole amount.
• Formula to find out unknown whole amount: unknown whole amount = partial amount divided by percentage value (if you using calculator).
• For example 45 is 15% of what amount? So 45 / 15% = 300 (so 45 is 15% of 300).

Example 1: 54.45 is 25% of what amount?

Solution: Unknown whole amount = Partial amount (54.45) / Percentage (25%) (if you using calculator)

Or

25 / 100 = 0.25 (to covert percentage into decimal, simply divide by 100)

54.45 / 0.25 = 217.8 (so 54.45 is 25% of 217.8)

### Case 4: How To Calculate Discounts

Here we have explained simple method to find out discounted amount.

• Firstly convert discount percentage into decimal and to covert percentage into decimal just simply divide percentage value by 100 for example – if discount is 15% so just divide 15 by 100 and you will get percentage into decimal value which would be 0.15 (this value is in decimal).
• Now, multiply decimal value (which is decimal form of percentage value) with the original price for example – if original price of an item is \$799 then simply multiply 0.15 with 799 and you will get discounted amount which would be \$119.85 (this amount you getting as a discount).
• Now to find out the selling price (or money you have to pay after the discount) of that item, just subtract the discounted amount from the original price for example 799 – 119.85 = 679.15 (so you will pay \$679.15 for that item).

Example 1: What amount will you pay if the original price of dress is \$1500 and discount on it is 10%?

Solution: Original price of dress is \$1500

Discount: 10% so 10 / 100 = 0.1 (to covert percentage into decimal, simply divide by 100)

Discounted amount: 0.1 * 1500 = 150 (this is discounted amount)

Amount you will pay for dress (or selling price of dress): 1500 – 150 = 1350 (so \$1350 you need to pay after the discount)

Example 2: Suppose you shop 1 shirt worth of \$300, 1 trouser pant worth of \$1500, pair of shoes worth of \$500 so what amount will you pay if discount is 20% on whole shopping?

Solution: Original price of whole shopping is \$2300 (\$300 + \$1500 + \$500 = \$2300)

Discount: 20% so 20 / 100 = 0.2 (to covert percentage into decimal, simply divide by 100)

Discounted amount: 0.2 * 2300 = 460 (this is discounted amount)

Amount you will pay for whole shopping (or selling price of whole shopping): 2300 – 460 = 1840 (so \$1840 you need to pay after the discount)

### Case 5: How To Calculate Sales Performance in Percentage

Here we have explained simple method to find out sales performance in percentage.

• Subtract current month sales by previous month sales for example – if your company sales in January 2019 were 107 units and in February 2019 sales are 120 units so you will do 120 – 107 = 13
• Now divide the difference (which is 13) by previous month sales for example 13 / 107 = 0.12
• Now you need to convert this value “0.12” into percentage, so for that just multiply it by 100 for example 0.12 * 100 = 12% (so your company sales in Feb 2019 is increased by 12%).

Example 1: Suppose your company sale in 2019 is \$2300 and sale in 2018 was \$2000. So what is the company sales performance in 2019? Give the sales performance in percentage.

Solution: Sales in 2019 = \$2300 (current year sales)

Sales in 2018 = \$2000 (previous year sales)

Sales performance in percentage = current year sales (subtract {-}) previous year sales (divide by {/}) previous year sales

2300 – 2000 = 300

300 / 2000 = 0.15

0.15 * 100 = 15% (so company sales in 2019 is increased by 15%)

Example 2: Suppose your company sale in 2019 is \$1800 and sale in 2018 was \$2100. So what is the company sales performance in 2019? Give the sales performance in percentage.

Solution: Sales in 2019 = \$1800 (current year sales)

Sales in 2018 = \$2100 (previous year sales)

Sales performance in percentage = current year sales (subtract {-}) previous year sales (divide by {/}) previous year sales

1800 – 2100 = 300

300 / 2100 = 0.14

0.14 * 100 = 14% (so company sales in 2019 is decreased by 14%)

#### 1 COMMENT

1. neilson

nice…