How to calculate a percentage of a number
Divide the percentage by 100 to convert it to decimal form, then multiply the decimal by the number.
How to find what percentage one number is of another
Divide the first number by the second number and multiply the result by 100.
How to calculate percentage increase or decrease
Subtract the original value from the new value. Divide the difference by the original value, then multiply by 100.
If a price increases from 100 to 125, the increase is 25%. If it drops from 100 to 75, the result is a 25% decrease.
Common percentage examples
Percentages are commonly used for discounts, tax, tips, price changes, grades, statistics, commissions and financial comparisons.
Frequently asked questions
What does percent mean?
Percent means “per hundred.” For example, 25% means 25 out of every 100.
How do I convert a percentage to a decimal?
Divide the percentage by 100. For example, 20% becomes 0.20.
How do I calculate a percentage increase?
Subtract the original value from the new value, divide by the original value, and multiply by 100.
Can percentage change be negative?
Yes. A negative percentage change represents a decrease from the original value.
Using this calculator effectively
Use this calculator when you need a percentage result without rearranging formulas by hand. It covers three common intents: finding a percentage of a value, finding what percent one value is of another, and measuring percentage change.
Common uses
- Checking discounts, markups, commissions and tax percentages.
- Comparing one value with another as a percentage.
- Measuring increases or decreases between an old and a new value.
Tips for a better estimate
- Use the same units for values you are comparing.
- For percentage change, confirm which number is the original or starting value.
- Keep extra decimal places until the final step if the result will be used in another calculation.
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