Percentage Calculator
Calculate percentages, percentage of a total, and percentage increase or decrease.
Find a percentage of a number
Example: What is 20% of 500?
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What percentage is one number of another?
Example: 50 is what percent of 200?
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Percentage increase or decrease
Enter the old value and new value.
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Three Percentage Formulas
A. Percentage of a number
Formula: (Percentage ÷ 100) × Number
Example: 20% of 500 = 100
B. One number as a percentage of another
Formula: (Number ÷ Total) × 100
Example: 50 out of 200 = 25%
C. Percentage increase or decrease
Formula: ((New Value − Old Value) ÷ |Old Value|) × 100
Examples: 100 to 125 = 25% increase; 100 to 75 = 25% decrease.
Percentage change from an old value of zero is undefined because division by zero is not possible.
Practical Uses of Percentages
Percentages make it easier to understand discounts, marks or scores, price changes, growth or decline, and comparisons between values. This calculator is intended for general calculations.
Percentage vs Percentage Points
If a rate changes from 20% to 25%, it increases by 5 percentage points. Relative to the original 20%, the percentage increase is 25%.
Frequently Asked Questions
How do I calculate 20% of a number?
Multiply the number by 20 and divide by 100. For example, 20% of 500 is 100.
How do I find what percentage one number is of another?
Divide the first number by the total and multiply the result by 100.
How do I calculate percentage increase?
Subtract the old value from the new value, divide by the absolute old value, and multiply by 100.
Can the old value be zero when calculating percentage change?
No. An old value of zero would require division by zero, so the percentage change is undefined.
What is the difference between percentage and percentage points?
Percentage points show the direct difference between two percentage rates. Percentage change shows the relative change from the original rate.