Percentage Calculator
A percentage calculator helps you solve common percentage problems quickly and accurately without doing mental math. Percentages are used everywhere in daily life, from calculating discounts and taxes to tracking changes in prices, scores, and statistics. A percentage simply means a part per hundred, so 25% means 25 out of every 100. This calculator handles the most common percentage calculations: finding what percentage one number is of another, calculating a percentage of a number, and determining percentage increase or decrease between two values. Whether you are a student checking homework, a shopper comparing discounts, a business owner calculating profit margins, or an analyst tracking growth rates, percentages are an essential tool. Understanding percentages also helps you interpret statistics in news reports, understand interest rates on loans, and compare investment returns. The key is remembering that percentage is always relative to a base value, so the same percentage means very different amounts depending on what it is applied to.
Formula
Percentage of a number: Result = (Percentage / 100) x Number What percentage is A of B: Percentage = (A / B) x 100 Percentage increase/decrease: Change = ((New - Old) / Old) x 100
Example
Example 1 - Percentage of a number: What is 20% of 150? = (20 / 100) x 150 = 30 Example 2 - Percentage of total: 30 is what % of 150? = (30 / 150) x 100 = 20% Example 3 - Percentage increase: Price goes from $100 to $150 = ((150 - 100) / 100) x 100 = 50% increase Example 4 - Percentage decrease: Price drops from $100 to $80 = ((80 - 100) / 100) x 100 = -20% (20% decrease) Result: Percentages let you compare values relative to a base. Always identify the base (the 'of' number) before calculating.
How to Use
- Enter the values for the calculation you need.
- For percentage of a number: enter the percentage and the number.
- For percentage of total: enter the part and the total.
- For increase/decrease: enter the old value and the new value.
- Click Calculate to see the result with the formula shown.
Frequently Asked Questions
What is a percentage?
A percentage is a way of expressing a number as a fraction of 100. The word comes from the Latin 'per centum', meaning 'by the hundred'. So 25% means 25 out of 100, or one quarter. Percentages are used to compare proportions, show changes, and express ratios in a way that is easy to understand.
How do I calculate a percentage of a number?
To find a percentage of a number, convert the percentage to a decimal by dividing by 100, then multiply by the number. For example, to find 20% of 150, calculate (20 / 100) x 150 = 30. Alternatively, multiply the number by the percentage and divide by 100: (150 x 20) / 100 = 30.
How do I calculate percentage increase?
To calculate percentage increase, subtract the original value from the new value, divide by the original value, and multiply by 100. For example, if a price increases from $100 to $150, the increase is ((150 - 100) / 100) x 100 = 50%. Always divide by the original (older) value, not the new one.
What is the difference between percentage and percentile?
A percentage is a fraction of 100, representing a part of a whole. A percentile is a measure of rank, indicating the percentage of values that fall below a given value in a dataset. For example, scoring in the 90th percentile means you scored higher than 90% of the other test takers, not that you got 90% of the questions right.
How do I calculate percentage difference between two numbers?
Percentage difference is used when comparing two values without a clear original. Calculate the absolute difference, divide by the average of the two values, and multiply by 100. For example, the percentage difference between 100 and 150 is |100 - 150| / ((100 + 150) / 2) x 100 = 40%.
Why do percentages matter in finance?
Percentages are essential in finance for comparing interest rates, returns, discounts, taxes, and changes in value. A 5% return on $10,000 is $500, but a 5% return on $100,000 is $5,000. Percentages let you compare investments of different sizes on equal footing, which is why they are used for APR, APY, ROI, and growth rates.