Everyday math
Turn percentage questions into clear math.
Choose the question you are trying to answer, enter two values, and see both the result and the formula.
Your result
Enter two values to calculate.
Math used
The key idea
Percent means “per hundred.” Converting a percentage to a decimal divides it by 100, so 25% becomes 0.25. Finding 25% of 80 is therefore the same as multiplying 0.25 by 80.
Percent of a whole
Divide the part by the whole, then multiply by 100. If 20 of 80 items are selected, 20 / 80 x 100 = 25%.
Percentage change
Subtract the starting value from the ending value, divide by the absolute starting value, then multiply by 100. The starting value is the comparison base.
Percentage points differ
A rate moving from 20% to 25% rises 5 percentage points, but the relative increase is 25% because 5 is one quarter of the original 20.
This calculator performs general arithmetic. Rounding, measurement precision, and the meaning of the comparison base can affect how a percentage should be interpreted.
Keep calculating
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