Learning how to calculate the percentage of one number vs. another number is easy. If you want to know what percent A is of B, you simple divide A by B, then take that number and move the decimal place two spaces to the right. That's your percentage!
To use the calculator, enter two numbers to calculate the percentage the first is of the second by clicking Calculate Percentage. You may also calculate the value of a percentage of a number by entering the percentage you seek of the number you also enter and then clicking Calculate % Value.