How it is calculated
A percent of a number is the number multiplied by the percent and divided by 100. A share answers what part one number is of another. Change measures the difference against the starting number, not against the larger of the two.
Change, % = (After − Before) / |Before| × 100
Where the numbers come from
- Action
- Number
- A percent or a share — In “What share” mode this is the part, and “Number” is the whole.
- Before
- After
Example
It was 80 and it became 100. The gain = (100 − 80) / 80 × 100% = 25%. Going back from 100 to 80 is already minus 20%, because the base is different.
Questions
Why are a rise of 25% and a drop of 20% about the same pair of numbers?
Because a percent is always taken from a base. From 80 to 100 the base is 80. From 100 to 80 the base is 100.
How do I add 20% to 500?
“Add on” mode. 500 × 1,2 = 600.
Can I enter percents with a comma?
Yes. Both 12,5 and 12.5 will work.