X is P Percent of What Calculator
Find the whole number when you know a value and the percentage it represents. For example: 12 is 40% of what number? Enter the value and percentage below to get the answer instantly.
How It Works
This is a reverse percentage calculation. You know the part and what percentage of the whole it represents, and you need to find the whole. To do this, divide the known value by the percentage expressed as a decimal (i.e. divide by percentage, then multiply by 100).
The Formula
Whole = X / (P / 100)
Or equivalently: Whole = (X x 100) / P
Common Uses
This calculation is useful when you know a subset of a group and the percentage it represents, and you want to find the total. For example: 15 students passed, which is 60% of the class. How many students are in the class? Or: you saved £45, which is 30% of the original price. What was the original price?
Worked Examples
Example 1: 12 is 40% of what?
12 / (40 / 100) = 12 / 0.4 = 30
Example 2: 45 is 75% of what?
45 / (75 / 100) = 45 / 0.75 = 60
Example 3: 18 is 25% of what?
18 / (25 / 100) = 18 / 0.25 = 72
Example 4: 7 is 35% of what?
7 / (35 / 100) = 7 / 0.35 = 20
Example 5: 120 is 80% of what?
120 / (80 / 100) = 120 / 0.8 = 150
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Reverse Percentage
Work backwards from a result to find the original value.