If you need to calculate the given value as how much percentage of a total value then do as follows.
Step 1 : In the below example we need to calculate the count in A2 is how much percentage of B2. To do that we have just divided A2 by B2 (using simple formula ‘A2/B2’) in cell C2.
Step 2 : Now select the cell C2 and click on the Percentage(%) symbol available in ‘Number’ group of ‘Home’ tab in toolbar. To apply Percent format you can also use the Keyboard Shortcut Ctrl+Shift+%
Step 3: In the Number group of same Home tab, click on the Increase/Decrease Decimal button as shown in the below picture to determine the decimal digit count. Here I pressed the left one twice to show the percentage till 2 decimal points in cell C2.