Time & Everyday
Percentage Calculator
The three percentage questions that actually come up, each in its own row.
What is X% of Y?
% of
=
36
X is what percent of Y?
is what % of
=
25%
Percent change from A to B
From to
=
+25%
How the math works
Percent of a number is the percent divided by 100, times the number: 15 percent of 240 is 0.15 times 240, which is 36. A share is the part divided by the whole: 45 out of 180 is 0.25, or 25 percent.
Percent change compares the difference to where you started. Going from 80 to 100 is a gain of 20 on a base of 80, so +25 percent. Going back from 100 to 80 is minus 20 on a base of 100, which is only minus 20 percent. The base is why the same move reads differently in each direction.