Social Security benefits have become an increasingly important part of many Americans' retirement strategies. Yet few people actually know how their benefits are calculated.

In December alone, an estimated 38 million people received nearly $50 billion in retirement benefits, equating to an average of $1,294 per month. Should your monthly check be bigger than this? And, if so, why or why not?

As I explain in the slideshow below, the size of your benefits is primarily a function of how much you earned over the course of your working life. The more you earned, the higher your benefits will be.

Of course, there's more to the analysis than this. But at the end of the day, as you'll see by scrolling through the short presentation below, it doesn't take a mathematician to fully grasp the ins and outs of the Social Security benefit formula.