Retirement is something you have a lifetime to prepare for. Shockingly, far too many Americans reach their later years woefully unprepared for the years ahead.

In fact, these four hard-to-believe facts about retirement reveal just how dire a financial situation millions of seniors are facing. 

Older couple using calculator and reviewing financial papers.

Image source: Getty Images.

1. Baby Boomers have shockingly low median savings

Boomers are in retirement already, or close to it. Yet, a recent study from the Transamerica Center for Retirement Studies found the median savings among this cohort was just $152,000 across all retirement accounts. 

This would produce only about $6,080 in annual retirement income for Boomers following the 4% rule. Obviously, that's not enough to have a comfortable retirement. 

2. Even many high earners struggle to save for retirement 

You may think it's just low- and middle-income Americans who struggle to invest for retirement, but that's not the case. According to research from the New School, 27% of workers whose incomes exceed the Social Security wage base limit had absolutely nothing saved for retirement. 

That's a surprising stat, as the Social Security wage base limit in 2020 is $137,700. That means nearly three in 10 Americans with incomes in the mid-six figures haven't been able to put away any money for their futures. 

3. Social Security is the primary source of income for more than half of Americans

The Social Security Administration reports half of all married couples and 70% of unmarried seniors get at least 50% of their household money from their retirement benefits. And 21% of married couples and 45% of singles receive 90% or more of their household income from Social Security. 

This may not seem like a shocking statistic at first glance. After all, you probably assume you're supposed to get the bulk of your funds from Social Security. However, it becomes far more surprising when you look at the average benefit, which is expected to be $1,543 per month in January 2020. 

With Social Security checks so low, seniors relying on them for most or all of their income could be left with around $18,516 to live on unless their benefits are far higher than the typical amount. That isn't exactly enough for a lavish retirement. 

4. Healthcare costs could take up more than 20% of the average Social Security benefit

According to the Bureau of Labor Statistics, mean household spending on healthcare is $6,833 per year for those 65 and older. A household is defined as having 1.7 persons, so that equates to around $4,019 per individual senior. Unfortunately, that amount could eat up about about 22% of the average Social Security benefit, leaving seniors with little money for other needs. 

Some retirees will also spend much more than the mean. In fact, the Employee Benefit Research Institute found that a senior man turning 65 this year would need $130,000 saved to have a 90% chance of covering medical expenses throughout retirement, while a senior woman would need $146,000. This is out-of-pocket expenses for those with high prescription drug needs who are covered by Medicare. 

With healthcare so expensive, Social Security benefits providing so little income, and so many retirees having little savings, that's a recipe for disaster. Of course, you can beat the averages when it comes to both savings and your Social Security benefit -- if you make a few key decisions throughout your life. Start saving money early, aim to contribute around 15% to 20% of your income to tax-advantaged retirement funds, and invest the money wisely. You can also explore options to maximize your Social Security benefits.

By taking these smart steps, you'll be ready to cover high healthcare costs as a retiree and still hopefully have plenty of money left over to enjoy life.