How to calculate percentage
Answers
First: work out the difference (increase) between the two numbers you are comparing.Increase = New Number - Original Number.Then: divide the increase by the original number and multiply the answer by 100.% increase
step 1
Visualize what a percentage represents. A percentage is an expression of part of the whole. Nothing is represented by 0%, and the whole amount is 100%. Everything else is somewhere in between![1]
For example, say you have 10 apples. If you eat 2 apples, then you have eaten 2 out of the whole 10 apples (2 / 10 × 100% = 20% eaten). If 10 apples is 100% and you ate 20%, then 100% - 20% = 80% of the apples remain.
The term "percent" in English comes from the Latin per centum, meaning “through 100” or “for 100”.
step2
Determine the value of the whole. In some cases, you will be given the value for part of the whole and the whole. Other times, you might get two parts that make up the whole. It is important to distinguish what the percentage is “of.” For instance, let's say we have a jar containing 1199 red marbles and 485 blue marbles, making it 1684 marbles in total. In this case, 1684 makes up a whole jar of marbles, i.e. 100%.[2]
step3
Find the value that you want to turn into a percentage. Let's say we want to find out the percentage of the jar that is taken up by the blue marbles. Then the percentage of the whole we are looking for is 485 (the number of blue marbles) of 1684 (the whole amount).[3]
step 4
Put the two values into a fraction. The part goes on top of the fraction (numerator), and the whole goes on the bottom (denominator). Therefore the fraction in this case is 485/1684 (part/whole).[4]