Calculate percentages quickly and easily. Find a percentage of a number, determine what percentage one number is of another, or calculate percentage increase and decrease.
A percentage tells you how big one number is compared to another, expressed as a fraction of 100. To find what percentage a "part" is of a "whole," divide the part by the whole and multiply by 100.
To find a percentage of a number, convert the percentage to a decimal fraction by dividing by 100, then multiply it by the number.
This works the same way for quantities with units, since the math doesn't care what's being measured -- 20% of 5 GB is 1 GB, and 20% of $5 is $1. The calculation is identical; you just keep whatever unit the original quantity was in.
Percentage increase measures how much a value has grown, relative to where it started. Subtract the original value from the new value, divide by the original value, then multiply by 100.
Note that a percentage increase isn't the same thing as a "percentage point" change -- going from 40% to 50% is a 25% relative increase, but it's also described as a 10 percentage-point increase. See Percentage Points vs Percentages for a full explanation of the difference.
Percentage decrease measures how much a value has fallen, relative to where it started. Subtract the new value from the original value, divide by the original value, then multiply by 100.
| Calculation | Answer |
|---|---|
| 10% of 100 | 10 |
| 15% of 200 | 30 |
| 20% of 500 | 100 |
| 25% of 200 | 50 |
| 30% of 300 | 90 |
| 50% of 500 | 250 |
| 75% of 400 | 300 |
| 20% of 5 | 1 |
| 45.5 out of 60 | 75.83% |
Sometimes you know a result and the percentage it represents, but need to work backward to the original number -- for example, "552 is 92% of what number?" Divide the result by the percentage (as a decimal) to find it.
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A percentage is a way of expressing a number as a fraction of 100. The symbol "%" means "out of 100" — for example, 25% means 25 out of every 100.
Divide the percentage by 100, then multiply by the number: (Percentage ÷ 100) × Number. For example, 25% of 200 is (25 ÷ 100) × 200 = 50.
Divide the part by the whole, then multiply by 100: (Part ÷ Whole) × 100. For example, 50 is (50 ÷ 200) × 100 = 25% of 200.
Divide the result by the percentage, expressed as a decimal: Original = Result ÷ (Percentage ÷ 100). For example, if 552 is 92% of a number, that number is 552 ÷ 0.92 = 600.
Subtract the original value from the new value, divide by the original value, then multiply by 100: ((New − Original) ÷ Original) × 100. Going from 100 to 150 is a 50% increase.
Subtract the new value from the original value, divide by the original value, then multiply by 100: ((Original − New) ÷ Original) × 100. Going from 150 to 100 is a 33.33% decrease.
Yes. All four calculator modes accept decimal values, and results are rounded to two decimal places so answers stay easy to read.
Yes. The math is the same regardless of unit -- 20% of 5 GB is 1 GB, and 20% of $5 is $1. Enter just the number into the calculator; the unit stays whatever it started as.
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