Percentage Calculator

Percentages are a fundamental concept in mathematics and everyday life. Whether you're calculating discounts during a sale, evaluating your investment returns, or analyzing data, percentages play a significant role. In this comprehensive guide, we'll delve into the world of percentages, exploring what they are, how to calculate them, and revealing some secrets that will make percentage calculations a breeze.

What Is a Percentage?

A percentage is a way of expressing a number or ratio as a fraction of 100. It's derived from the Latin term "per centum," which means "by the hundred." Percentages are used to compare quantities, represent proportions, and make data more understandable.

Percentage Formula

To express a number as a percentage, you can use the following formula:

Percentage (%) = (Part / Whole) * 100


  • Percentage (%): The result expressed as a percentage.
  • Part: The portion of the whole that you're evaluating.
  • Whole: The complete quantity or the total.

How to Calculate Percentages

Calculating percentages can be a straightforward process when you understand the underlying concept. Here are some common scenarios where you might need to calculate percentages:

  • Calculating a Percentage of a Number: To find a specific percentage of a number, use the formula above.
  • Calculating the Percentage Change: To determine the percentage change between two numbers, use the following formula:

Percentage Change (%) = [(New Value - Old Value) / |Old Value|] * 100

  • Calculating Discounts: To find the final price after a discount, use the following formula:

Final Price = Original Price - (Original Price * Discount Percentage)

Percentage Calculator Secrets

Now, let's uncover some secrets and tips to simplify percentage calculations:

  1. Convert Decimals to Percentages: To convert a decimal to a percentage, multiply by 100 and add a percentage sign.
  2. Reverse Percentage Calculation: If you know the percentage and the part, you can calculate the whole using this formula:

Whole = Part / (Percentage / 100)

  1. Calculating Compound Interest: When calculating compound interest, use this formula:

A = P(1 + r/n)^(nt)


  • A: The final amount, including principal and interest.
  • P: The principal amount.
  • r: The annual interest rate (decimal).
  • n: The number of times that interest is compounded per year.
  • t: The number of years.
  1. Understanding Percentage Points: Be aware of the difference between percentages and percentage points. Percentage points measure the difference between two percentages.


Percentages are a versatile tool for expressing and analyzing data. With a solid understanding of the concept and some handy formulas, you can confidently navigate percentage calculations in various real-life situations. Whether you're working with financial data, evaluating trends, or simply trying to calculate a tip, percentages will be your trusted companion.

Remember that practice makes perfect, and as you apply these percentage calculation techniques, you'll become more adept at using percentages in your daily life.