Percentage Calculator Online

Last updated: June 9, 2025Math Tools

A percentage calculator is a tool that helps you perform percentage based calculations quickly and accurately.

Example:

What is 20% of 150?

150 × 20% = 30

What Is a Percentage?

A percentage is a way of expressing a number as a fraction of 100. The symbol "%" denotes percent, so 40% means 40 out of 100 or simply 0.4 in decimal form. Percentages are widely used in finance, statistics, exams, and daily calculations.

Percentage Syntax

The basic syntax for a percentage statement is:

percentage = (part / whole) × 100
  • Part: The number you want to convert to a percentage.
  • Whole: The total number of items or the base value.
  • Percentage: The result of the percentage calculation.

Key Percentage Formulas

1. Finding What Percent One Number Is of Another

Percentage = (Part / Whole) × 100

Example:

Your business made $1,500 this month and $2,000 last month. What percent of last month's sales did you make this month?

Percentage = (1500/2000) × 100 = 0.75 × 100 = 75

This month's sales were 75% of last month's.

2. Finding the Percentage of a Number

Part = (Percentage / 100) × Whole

Example:

Monthly Income: $2,000

You decide to spend 10% of your income on groceries.

Part = (10 / 100) × 2000 = $200

You will spend $200 on groceries.

3. Finding the Whole from a Part and Percentage

Whole = Part / (Percentage / 100)

Example:

You saved $200, which is 20% of your monthly income. What's your total income?

Whole = 200 / (20 / 100) = $1000

Your income is $1000.

4. Percentage Increase/Decrease

Percentage Increase/Decrease = ((New Value - Original Value) / Original Value) × 100

Example:

Your salary was $5000 last year and $6000 this year. What's your percentage increase?

Percentage Increase = ((6000 - 5000) / 5000) × 100 = 20%

Your salary increased by 20%.

Why Is Percentage Important?

Percentage is a fundamental math operation that goes beyond just basic arithmetic problems. It plays a critical role in many aspects of our lives, from managing personal finances to understanding the world around us.

Daily Life

Calculate discounts, tips, and interest rates. Understand and compare quantities, make informed decisions, and solve everyday problems.

Foundation for Math

Master percentage to learn more complex mathematical concepts, such as ratios, proportions, and statistics. Build a strong foundation for understanding mathematical relationships and applying mathematical models to real-world problems.

Critical Thinking and Problem-Solving

Develop critical thinking and problem-solving skills with percentage. Analyze information, recognize patterns, and make logical connections between different pieces of data. Evaluate information, make informed decisions, and solve complex problems in a wide range of subjects.

Practical Applications of Percentage Calculators

1. Finance and Banking

Percentage calculators help with interest rates, loan payments, and investment returns, streamlining personal and commercial financial decisions.

2. Personal Budgeting

They enable users to allocate income across expenses, savings, and debt, promoting better money management and planning.

3. Business and eCommerce

Used to calculate profit margins, markups, discounts, and taxes, they improve pricing, revenue analysis, and sales strategies.

4. Education and Grading

Educators and students use them to assess scores, weighted averages, and academic performance quickly and accurately.

5. Health and Fitness

Essential for measuring body fat, tracking progress, and calculating macronutrient ratios for tailored nutrition and workout plans.

Conclusion

Percentage calculators are powerful tools that simplify complex numerical tasks across various sectors. From finance to fitness, they enhance accuracy, save time, and support better decision-making. Their versatility makes them essential for both personal and professional use.