One way to calculate percentages is to use this general percentage formula:
%  =  part 
100  whole 
This tool calculates what percent of a number is another number. If you know any two values of the formula, you can calculate the third one. In this example, you know the 'part' (22) and the 'whole' (88). So, you can find the 'percentage'.
By replacing the given values in the formula, you get:

or 

Crossmultiply the last equation:
% × 88 = 22 × 100
Divide by 88 and get the percentage:
%  =  22 × 100  =  25%  
88 