How to Calculate Percentage?

The term “percentage” is derived from the Latin word “per centum”, which means “by the hundred”. So, to Calculate percentage, the whole part is taken as 100. Percentages are everywhere – from calculating exam scores to shopping discounts and financial growth. If you’ve ever wondered how to calculate the percent of a number or turn a value into a percentage, this complete guide will walk you through every step. Whether you’re a student, professional, or just curious, mastering percentages is essential.

For example, if a student scores 36 out of 60 in science, then the percentage can be calculated by expressing the marks obtained as a fraction of the total marks, and multiplying the result by 100.

i.e.,
percentage of marks = $$[
\left( \frac{36}{60} \right) \times 100 = 60\%
]$$

What is a Percentage?

A percentage is a number or ratio expressed as a fraction of 100. It’s denoted by the symbol “%” and is used to show proportions, comparisons, and changes in values. For example, 40% means 40 out of 100.

Understanding Percentage

Percentages simplify how we talk about parts of a whole. Whether you’re figuring out what portion of your salary is spent on rent or what percent of your class passed the test, percentages offer an easy way to interpret and compare numbers.

Common Uses of Percentages in Real Life

• Discounts and Offers: 30% off a product
• Exam Scores: 85% in math
• Finance: 6% interest on savings
• Data Analysis: Survey results, growth trends

Percentage Formula with Example

The standard formula for calculating percentage is:

Percentage (%) = $$[
\left( \frac{\text{Part}}{\text{Whole}} \right) \times 100
]$$

Example: If you scored 45 out of 60 in a test, your percentage is:

$$[
\left( \frac{45}{60} \right) \times 100 = 75\%
]$$

How to Calculate Percentage of a Number

To find a specific percentage of a value, use this formula:

Percentage Value = $$[
\left( \frac{\text{Percentage}}{100} \right) \times \text{Total Number}
]$$

Example: $$[
20\% \text{ of } 150 = \left( \frac{20}{100} \right) \times 150 = 30
]$$

How to Calculate Percentage of Marks

Use the same formula:

Marks Percentage = $$[
\left( \frac{\text{Marks Obtained}}{\text{Total Marks}} \right) \times 100
]$$

Example: $$[
\left( \frac{68}{80} \right) \times 100 = 85\%
]$$

Another Example: If a student scores 15 out of 50 in math, then:

Percentage = $$[
\left( \frac{15}{50} \right) \times 100 = 30\%
]$$

Another Example: If a student scores 36 out of 60 in science, then:

Percentage = $$[
\left( \frac{36}{60} \right) \times 100 = 60\%
]$$

How to Calculate Percentage of Money

For tips, taxes, and interest:

Example: $$[
18\% \text{ tip on } \$50 = \left( \frac{18}{100} \right) \times 50 = \$9
]$$

How Do I Calculate What Percentage One Number Is of Another?

Use this reverse formula:

Percentage = $$[
\left( \frac{\text{Part}}{\text{Whole}} \right) \times 100
]$$

Example: $$[
30 \text{ is what percent of } 120? \quad \left(\frac{30}{120}\right) \times 100 = 25\%
]$$

How to Calculate Total Given a Percentage

When you’re given a part and the percentage, and need to find the whole:

Total = $$[
\text{Whole} = \frac{\text{Part}}{\left(\frac{\text{Percentage}}{100}\right)}
]$$

Example: $$[
\text{Number} = \frac{50}{0.25} = 200
]$$

How to Calculate Percentage Off a Value (Discount)

To calculate how much you save:

Discount = $$[
\left(\frac{\text{Discount \%}}{100}\right) \times \text{Original Price}
]$$

Example: $$20\% \text{ off } \$80 = \left(\frac{20}{100}\right) \times 80 = \$16$$

Final Price = $80 – $16 = $64

How to Convert a Value into a Percentage

Use this formula:

$$\left(\frac{\text{Value}}{\text{Total}}\right) \times 100$$

Example: $$\left(\frac{45}{90}\right) \times 100 = 50\%$$

What is the Formula for Converting to Percentages?

Standard formula:

Percentage = $$\left(\frac{\text{Part}}{\text{Whole}}\right) \times 100$$

How to Quickly Calculate Percentages

• 10% of a number: Move the decimal one place left.
• 5%: Half of 10%
• 1%: Move two places left
• 20%: Double 10%

Example: $$20\% \text{ of } 80 = 8 + 8 = 16$$

Percentage Increase and Decrease

Percentage Increase:

$$\left( \frac{\text{New Value} – \text{Original Value}}{\text{Original Value}} \right) \times 100$$

Percentage Decrease:

$$\left( \frac{\text{Original Value} – \text{New Value}}{\text{Original Value}} \right) \times 100$$

Percentage Difference Calculator

To find the percentage difference between two values:

$$\left( \frac{|\text{Value}_1 – \text{Value}_2|}{\frac{\text{Value}_1 + \text{Value}_2}{2}} \right) \times 100$$

Example: Difference between 60 and 80 = $$\left( \frac{20}{70} \right) \times 100 \approx 28.57\%$$

Conversion Between Percentages, Decimals, and Fractions

• Decimal to Percent: Multiply by 100 (0.25 = 25%)
• Percent to Decimal: Divide by 100 (75% = 0.75)
• Fraction to Percent: (3/4) × 100 = 75%
• Percent to Fraction: 60% = 60/100 = 3/5

Percentage Formula in Excel

Use the formula: =$$\left( \frac{\text{Part}}{\text{Total}} \right) \times 100$$

Example: =$$\left( \frac{40}{200} \right) \times 100 = 20\%$$

Percentage Calculator Tool

Use our Percentage Calculator to save time:

• Calculate percentage of a number
• Find what percent one number is of another
• Work out discounts and markups instantly

Now that you know how to calculate percentages of numbers, marks, money, and more, you can confidently apply these formulas in school, work, or daily life. From calculating tips at dinner to analyzing your grades or tracking business growth – percentages are a powerful tool. Use our built-in Percentage Calculator to get answers fast, or practice the formulas manually to sharpen your math skills!

Frequently Asked Questions