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Percentage Calculator - Calculate Percentages Instantly Online

Free online percentage calculator. Calculate percentage of a number, percentage change, percentage difference, and more. Fast, accurate, and easy to use.

9 min read

iAbout This Calculator

The percentage calculator is an essential tool for everyday math calculations. Whether you need to calculate discounts while shopping, figure out tip amounts at restaurants, or analyze data for work or school, understanding percentages is crucial. Our free online percentage calculator handles all types of percentage calculations instantly, from finding what percentage one number is of another to calculating percentage increases and decreases. With a clean interface and accurate results, this tool makes percentage math accessible to everyone, regardless of mathematical background.

?How to Use

  1. 1

    Select the type of percentage calculation you want to perform from the dropdown menu. Options include: percentage of a number, percentage change, percentage increase/decrease, and finding what percent one number is of another.

  2. 2

    Enter your values in the designated input fields. For basic percentage calculations, enter the number and the percentage. For percentage change, enter both the original and new values.

  3. 3

    Click the Calculate button or wait for automatic calculation (if enabled). The result will display instantly below the input fields.

  4. 4

    Use the Copy button to copy results to your clipboard, or the Print button to generate a printable summary of your calculation.

  5. 5

    Review the step-by-step breakdown shown below the result to understand exactly how the calculation was performed.

fFormula

\text{Percentage} = \frac{\text{Part}}{\text{Whole}} \times 100

To find what percentage a number is of another, divide the part by the whole and multiply by 100. For example, to find what percentage 25 is of 200, divide 25 by 200 (0.125) and multiply by 100 to get 12.5%.

Part
The portion or subset you want to express as a percentage
Whole
The total or complete amount (the reference value)
Percentage
The result expressed as a value out of 100

Examples

Finding Percentage of a Number

Inputs: percentage: 15, number: 200
30

15% of 200 = (15/100) x 200 = 0.15 x 200 = 30

Calculating Percentage Change

Inputs: originalValue: 80, newValue: 100
25% increase

Change = 100 - 80 = 20. Percentage change = (20/80) x 100 = 25%

Finding What Percent One Number Is of Another

Inputs: part: 45, whole: 180
25%

45 is what percent of 180? (45/180) x 100 = 0.25 x 100 = 25%

Calculating Discounted Price

Inputs: originalPrice: 150, discountPercent: 20
$120

Discount amount = 20% of 150 = 30. Final price = 150 - 30 = $120

Use Cases

Shopping and Discounts

Calculate sale prices, compare discounts, and determine how much you save. Whether it's a 25% off sale or a buy-one-get-one deal, quickly figure out the actual savings.

Financial Planning

Compute interest rates, investment returns, and budget allocations. Understand what percentage of your income goes to different expenses.

Academic Grading

Convert raw scores to percentages, calculate GPA impact, and determine what score you need on finals to achieve your target grade.

Business Analytics

Analyze growth rates, market share changes, profit margins, and conversion rates. Make data-driven decisions with accurate percentage calculations.

Health and Fitness

Track body fat percentage, calculate macronutrient ratios, and monitor progress toward fitness goals expressed as percentages.

Frequently Asked Questions

How do I calculate percentage of a number?
To calculate a percentage of a number, convert the percentage to a decimal (divide by 100) and multiply by the number. For example, 25% of 80 = 0.25 x 80 = 20. Alternatively, multiply the number by the percentage and divide by 100.
What is the difference between percentage change and percentage difference?
Percentage change compares a new value to an original value and shows increase or decrease. Percentage difference compares two values to their average, useful when neither value is the 'original.' For example, comparing prices between two stores uses percentage difference.
How do I calculate percentage increase?
Use the formula: ((New Value - Original Value) / Original Value) x 100. If a product price went from $50 to $65, the increase is ((65-50)/50) x 100 = 30%. The price increased by 30%.
Why doesn't a percentage increase followed by the same percentage decrease return to the original?
Because each percentage is calculated from a different base. A 20% increase on $100 gives $120. A 20% decrease on $120 is $24, leaving $96 - not $100. The second calculation uses the new, larger base.
How do I reverse a percentage calculation?
To find the original number after a percentage was applied, divide by the percentage factor. If 30 is 15% of a number, the original is 30 / 0.15 = 200. If a price after 20% discount is $80, the original was 80 / 0.80 = $100.

Conclusion

Mastering percentage calculations empowers you to make better financial decisions, understand data more clearly, and solve everyday math problems with confidence. Our percentage calculator provides instant, accurate results for all types of percentage calculations. Bookmark this tool for quick access whenever you need to work with percentages, and explore our related calculators for more mathematical tools.

Last updated: January 5, 2026

Author: CalcMaster Team

Reviewed by: Dr. Mathematics

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